<PAGE>   1
                                                                   Exhibit 10.5

        Portions of this exhibit have been omitted and filed separately
                  with the Securities and Exchange Commission.
                  Those portions are designated "[ * * * ]."

                                                                       EXHIBIT B


                                FIBER OPTIC LEASE


            THIS FIBER OPTIC LEASE ("Lease") is made as of this ____ day of
______________, 200__ between Pathnet Telecommunications, Inc., a Delaware
corporation ("Pathnet") and The Burlington Northern and Santa Fe Railway
Company, a Delaware corporation ("BNSF"). This Lease is being entered into
pursuant to the terms of that certain fiber optic access agreement between BNSF
and Pathnet dated November __, 1999 ("Fiber Optic Access Agreement"), which sets
forth the terms upon which BNSF granted to Pathnet the right to enter into fiber
optic leases, on the terms of this Lease, on specified rail corridors in the
BNSF rail transportation network and subject to all limitations on the ownership
interest of BNSF, to Construct and Operate Fiber Optic Facilities (as defined
below).

            WHEREAS, BNSF has certain ownership interests in a rail corridor
consisting of ___ route miles between ___________________ and
______________________ ("Rail Corridor");

            WHEREAS, Pathnet desires to lease from BNSF, on the terms and
conditions set forth herein, a portion of the Rail Corridor, in order for
Pathnet to construct, install, operate, maintain, replace, reconstruct, remove
and/or relocate (collectively, "Construct and Operate") a fiber optic
telecommunications transmission system and certain appurtenant equipment and
structures (collectively, "Fiber Optic Facilities"); and

            WHEREAS, BNSF is willing, on the terms and conditions set forth in
this Lease, to lease a portion of the Rail Corridor to Pathnet, for the sole
purpose of allowing Pathnet, subject to all limitations on the ownership
interest of BNSF, to Construct and Operate Fiber Optic Facilities on the Rail
Corridor.

            NOW THEREFORE, Pathnet and BNSF agree as follows:

            1. Lease Rights. Pursuant to the terms of this Lease and the Fiber
Optic Access Agreement, Pathnet shall have the right to enter upon a portion of
the Rail Corridor, which portion generally shall be a three foot wide strip of
land, or such larger portion required to Construct and Operate the Fiber Optic
Facilities, as specified in the Final Construction Plans (as defined later
herein) but at each repeater station or other required Fiber Optic Facilities
structure occupying more land, the portion shall extend one foot beyond the
perimeter of the structure or equipment, or, where a perimeter fence is built
around the structure or equipment, one foot beyond the perimeter fence, the
specific portion of the Rail Corridor leased ("Premises") being identified in
Exhibit A attached hereto and made a part hereof. All structures may be fenced
by Pathnet, at its sole cost and expense, and may be multiple stories to the
extent approved by BNSF, provided that the height and other dimensions of any
such structure do not interfere with railroad operations or clearance, or create
a safety hazard. Any such structures may exceed 3,500



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<PAGE>   2

square feet only: (i) subject to space availability; (ii) following prior
written approval of BNSF, not to be unreasonably withheld; and (iii) where such
structures are not buildings where people regularly report to work. Pathnet's
right to enter the Premises shall commence on the ___ day of ________________,
200__, and shall be for the sole purpose of allowing Pathnet, or any of its
permitted assignees, sublessees of capacity, agents, contractors, strategic or
co-development partners, customers or invitees, or any of their employees
(collectively, "Pathnet Parties") to Construct and Operate Fiber Optic
Facilities on the Premises, subject to BNSF's rights as set forth herein and all
contract and/or property rights of others in the Premises. Pathnet, and any of
the Pathnet Parties, also shall have the right to cross other property in which
BNSF has a sufficient ownership interest as required to access the Premises,
subject to BNSF's rights as set forth herein and all contract and/or property
rights of others in the Premises, so long as such access shall not cross any
active railroad track, or come within 25 feet of such track, without BNSF's
prior written consent, which will not be unreasonably withheld or delayed. Any
of the Pathnet Parties entering onto the Rail Corridor must first execute an
agreement with BNSF in the form of Exhibit "C-1" attached hereto and made a part
hereof, by which such party agrees to comply with BNSF's Contractor Requirements
set forth as Exhibit "C" attached hereto and made a part hereof (and Pathnet
acknowledges that any such Pathnet Party's execution of the Exhibit "C-1"
agreement shall not relieve Pathnet of its full responsibility hereunder for any
actions, omissions or the presence of such Pathnet Party on or near the Rail
Corridor). Pathnet may install as much fiber optic capacity (which term shall
include conduits, whether installed empty or with fiber) on the Premises as it
determines to be appropriate, and may add further fiber optic capacity during
the term of this Lease. Pathnet's rights under this Lease are granted without
covenant of title or quiet enjoyment and Pathnet acknowledges that one or more
other parties may have, or may claim to have, ownership rights in the Rail
Corridor, and may claim that Pathnet also must obtain rights from it (or them)
in order to occupy or access the Premises, and that, in some cases, such claims
may be valid. Pathnet acknowledges that segments of the Rail Corridor may
consist only of a trackage rights licensed to BNSF to enable BNSF to provide
rail service, or shared ownership with other railroads, and that BNSF may not
have rights to include these segments in any Lease to Pathnet. BNSF will use
reasonable efforts to make available to Pathnet all documents reasonably
requested by Pathnet that could be located in a reasonable search (and, at
BNSF's option, BNSF can require that Pathnet or Pathnet's agent conduct the
search, at Pathnet's cost), which documents concern BNSF's rights, and the
rights of others, which in BNSF's judgment affects the Premises and Pathnet's
rights under this Lease or which Pathnet may identify which reasonably relates
to its rights under this Lease. Pathnet acknowledges that BNSF shall not be
liable for any nondisclosure of any document other than nondisclosure resulting
from gross negligence or wilfull misconduct of BNSF. Pathnet shall keep
confidential all confidential and proprietary data contained in these documents
and shall not use it for any purposes other than as set forth herein. BNSF shall
have the right, without causing undue delay, to review documents prior to
permitting Pathnet or its agent to review those documents, and to redact
confidential and proprietary information contained therein. Where
confidentiality provisions apply to contracts requested by Pathnet under this
Section 1, BNSF shall describe for Pathnet the restrictions and interference
with Pathnet's rights that such contracts permit, and or the fiber optic
capacity that such contracts permit to be built in the Rail Corridor, to the
extent that BNSF determines that it can do so consistent with the terms of each
applicable confidentiality provision. If Pathnet determines that BNSF's
description in such


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<PAGE>   3

circumstances is insufficient, Pathnet shall so inform BNSF and BNSF shall use
good faith efforts to obtain promptly from the other party to the contract at
issue a waiver of the confidentiality provision. Pathnet's rights are subject
and subordinate to all outstanding rights and encumbrances on the Rail Corridor
(including, but not limited to, BNSF's mortgages) which BNSF has placed, or in
the future will place, on the Rail Corridor, and any and all easements, other
leases, licenses, permits or agreements which now or in the future relate to the
Rail Corridor, except that BNSF in the future shall not place any encumbrance
upon the Premises, or enter into any easement, lease, license, permit or
agreement covering any portion of the Premises, which would materially disrupt
Pathnet's ability to utilize the Fiber Optic Facilities under this Lease (and
Pathnet acknowledges that its ability to utilize such Fiber Optic Facilities
would not be materially disrupted if Pathnet is relocated to another location
within the Rail Corridor in accordance with the terms of Section 14 hereof, or
BNSF makes available to Pathnet the fiber optic rights that BNSF has reserved at
no charge payable by Pathnet to the holder of the land interest where such
rights are located (and Pathnet agrees that any cost of enforcing such rights
shall be the responsibility of Pathnet). Pathnet accepts the condition of the
Premises "AS IS, WHERE IS" and "WITH ALL FAULTS". BNSF DISCLAIMS ANY AND ALL
WARRANTIES, EXPRESS OR IMPLIED, THAT ARE NOT SPECIFICALLY SET FORTH HEREIN IN
SECTION 22 HEREOF.

            2. Limitations on Lease Rights. Pathnet's rights under this Lease
also shall be subject and subordinate to the prior and continuing rights: (i) of
BNSF (and/or any other party with rights from BNSF) to use and maintain all or
any portion of its Rail Corridor in operating, maintaining, reconstructing or
relocating railroad tracks, signals, communications, electric lines or any other
improvements, equipment or facilities related to providing rail service
(collectively, "Rail Facilities"); (ii) of BNSF to use, and to allow others to
use, all and any portion of the Rail Corridor for any purpose (subject to the
terms of Section 4 of the Fiber Optic Access Agreement), which would not
materially disrupt Pathnet's ability to utilize the Fiber Optic Facilities under
this Lease; (iii) of BNSF to market and/or develop all or any portion of the
Rail Corridor or other BNSF property to rail transportation customers,
utilities, municipalities and other third parties except as restricted by
Section 4 of the Fiber Optic Access Agreement; and (iv) of BNSF to convey to any
party all or any portion of the Rail Corridor, any improvements owned by BNSF on
its Rail Corridor, and any air rights above, or subsurface rights below, the
surface of the Rail Corridor, except that any such conveyance by BNSF after the
date of this Lease shall be subject to this Lease, to the extent permitted by
applicable laws and agreements entered into prior to the date of this Lease. The
provisions of this paragraph shall be subject to the provisions of the Fiber
Optic Access Agreement.

            3. Railroad Control. BNSF (and/or any other party with rights from
BNSF) shall have full control at all times over the operation of its railroad
and all Rail Facilities in the Rail Corridor. Pathnet's rights under this Lease
do not authorize Pathnet, or any of the Pathnet Parties, to interfere in any way
with any aspect of BNSF's (and/or such other party's) rail operations, or with
any Rail Facilities, on or near the Rail Corridor, or BNSF's (and/or such other
party) ability to maintain, reconstruct or relocate any Rail Facilities on or
near the Rail Corridor. Pathnet understands that various activities of BNSF, or
parties with rights through BNSF, could have the potential of interrupting
service provided by Pathnet's Fiber Optic Facilities. BNSF



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<PAGE>   4

understands that uninterrupted service via Pathnet's Fiber Optic Facilities is
of critical importance to Pathnet. Where BNSF knows about future activities
which, in BNSF's opinion, would have a reasonable potential of interrupting
service via Pathnet's Fiber Optic Facilities or otherwise materially interfering
with the Construction and Operation of the Fiber Optic Facilities, BNSF shall
provide notice thereof to Pathnet as far in advance as is practical under the
circumstances, and shall cooperate with Pathnet to attempt to avoid any such
service interruption. Any failure by BNSF to provide such notice or cooperation
shall not subject BNSF to any liability, costs, expenses, damages, losses or
claims to Pathnet or any of the Pathnet Parties, except where the failure is due
to the gross negligence or willful misconduct of BNSF.

            4. Fiber Optics Rights are Nonexclusive. The fiber optics rights
granted to Pathnet are nonexclusive, except to the extent set forth in Section 4
of the Fiber Optic Access Agreement.

            5. Term of Lease. The term of this Lease shall be for 35 years
years from the date set forth in Section 1, except this Lease shall be
terminated earlier, if any of the following circumstances occur, on the specific
date related to those circumstances, as follows:

               (a)      If Pathnet fails to deliver Proposed Construction Plans
                        (as defined herein) within one hundred twenty (120) days
                        after the date of this Lease, or such longer period as
                        may be reasonably necessary to cure such failure,
                        provided that Pathnet already has begun to cure such
                        failure, and continues diligently to cure until
                        completion;

               (b)      If Pathnet fails to reach Commencement of Construction
                        (which is defined herein as the date of award of the
                        primary construction contract for the segment of the
                        Rail Corridor covered by the Proposed Construction
                        Plans), within either: (i) sixty (60) days from the date
                        that the Proposed Construction Plans become Final
                        Construction Plans for that segment of the Rail
                        Corridor, or such longer period as may be reasonably
                        necessary to cure such failure, provided that Pathnet
                        already has begun to cure such failure, and continues
                        diligently to cure until completion; or (ii) thirty (30)
                        days from a later date agreed to in writing by BNSF;

               (c)      Upon Pathnet's submission of the Proposed Construction
                        Plans, Pathnet also will submit to BNSF a construction
                        schedule ("Construction Schedule") for BNSF's approval,
                        such approval not to be unreasonably withheld. Pathnet
                        acknowledges that BNSF desires that construction be
                        completed as promptly as possible and will take this
                        into account in preparing the Construction Schedule. The
                        Construction Schedule shall contemplate completion of
                        construction of Fiber Optic Facilities on the segment of
                        the Rail Corridor covered by the Proposed Construction
                        Plans as promptly after BNSF's final approval of the
                        Proposed Construction Plans as is commercially feasible,
                        taking into account issues of weather and season, and
                        time to complete title due diligence or respond as



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<PAGE>   5

                        reasonably required to any title problems that likely
                        would materially affect Pathnet's ability to Construct
                        and Operate the Fiber Optic Facilities, and to acquire
                        any necessary construction and operating permits. Upon
                        approval of the Proposed Construction Plans and
                        Construction Schedule, Pathnet will construct the Fiber
                        Optic Facilities in accordance with the Construction
                        Schedule and otherwise with all promptness and due
                        diligence, it being understood that modifications in the
                        Construction Schedule may be required due to issues
                        arising during construction. If at any time BNSF
                        believes that Pathnet has failed to construct the Fiber
                        Optic Facilities as promptly as commercially feasibly,
                        subject to Pathnet's right to suspend construction as
                        provided in this Subsection, BNSF may provide Pathnet
                        with written notice of this fact. If Pathnet does not
                        cure such failure within thirty (30) days after
                        receiving such written notice, then upon written notice
                        to Pathnet, BNSF may terminate the Lease, effective
                        immediately. Notwithstanding the foregoing, Pathnet may
                        suspend construction for up to two (2) years, upon
                        receiving BNSF's written approval, not to be
                        unreasonably withheld, if market considerations or
                        financial issues warrant such a suspension. During any
                        such suspension, Pathnet's exclusive right to negotiate
                        fiber optic agreements with respect to the Rail
                        Corridor, as set forth in Section 4(b)(2) of the Fiber
                        Optic Access Agreement, also shall be suspended.

               (d)      If Pathnet fails to provide the capacity required by
                        Section 8 hereof, and such failure continues for a
                        period of thirty (30) days after Pathnet receives
                        written notice of such failure, or such longer time as
                        may be reasonably necessary, provided that Pathnet
                        commences a cure within thirty (30) days and continues
                        diligently to cure until such cure is completed.

               (e)      If BNSF has required that Pathnet suspend construction
                        activities on the Premises for Pathnet's failure to
                        comply with any BNSF safety requirements, or on account
                        of Pathnet's interference with BNSF's rail operations or
                        maintenance activities, and within twenty four (24)
                        hours after written notice requiring suspension, Pathnet
                        has not suspended such activities.

            6. Effect of Termination of Lease. Immediately upon termination of
this Lease, or if Pathnet abandons any Fiber Optic Facilities under this Lease
for a period of three years (which term shall mean the failure either to have in
use or to dedicate commercially reasonable marketing efforts to sell conduit,
dark fibers or capacity on the Premises), Pathnet shall relinquish to BNSF
possession of the Premises, provided that, for one hundred eighty (180) days
following such date Pathnet shall have the obligation to, and may continue to
enter the Premises for, the sole purposes of: (i) removing all above ground
Fiber Optic Facilities, (ii) removing below ground fiber Optic Facilities as
desired by Pathnet or to the extent reasonably requested by BNSF, and (iii)
restoring the Premises substantially to their condition on the date of this
Lease, reasonable wear and tear and casualty excepted, or as approved by BNSF.
Failure by Pathnet to



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<PAGE>   6

comply with the foregoing sentence by one hundred eighty (180) days following
the date of termination shall entitle BNSF to treat all remaining Fiber Optic
Facilities as abandoned, and as the property of BNSF.

            7. BNSF's Right to Suspend Pathnet Construction and Operating
Activities. In the event that Pathnet or a Pathnet Party fails to comply with
BNSF safety or operational regulations, or interferes or is reasonably likely to
interfere with BNSF rail operations, BNSF may require that Pathnet immediately
suspend all construction and/or operating activities on the Rail Corridor. In
such event, BNSF shall make a good faith effort to make available by
teleconference to discuss with Pathnet, within four (4) hours after suspension,
an individual with sufficient authority to resolve the issue, who shall be
prepared to discuss the reason(s) for such suspension and to attempt to resolve
the issue. If the parties are unable to resolve the issue in such discussion,
then BNSF and Pathnet will escalate the issue to the next higher level of
management, and shall attempt to meet, at a mutually agreeable location, or,
failing that, will have a telephonic meeting, within twenty four (24) hours of
the work suspension, with the goal of resolving the issue at that meeting. The
parties will negotiate in good faith to resolve the issue, and to prevent the
occurrence of similar situations in the future.

            8. Fiber Optic Capacity for BNSF.

               (a)  BNSF has retained the right to use the Premises leased
hereunder to the extent of retaining the right to use fiber optic capacity as
described in this Section 8, either as located on the Rail Corridor or, at
BNSF's option, on an alternative portion of Pathnet's fiber optic network, to
the extent that BNSF's desired point of termination on Pathnet's network is
within [***] miles of BNSF's current rail network (which in this sentence shall
include the two rail corridors included as "Rail Corridors" in the Fiber Optic
Access Agreement and the rail corridors where rail service operating rights
were sold to shortline railroads by BNSF or one of its predecessors and BNSF
retained fiber optic rights in the shortline rail corridor, as such current
rail network is shown on the map identified on Exhibit B). A map generally
depicting BNSF's current rail network is attached as Exhibit B. Accordingly,
Pathnet shall make available to BNSF, on an annual basis each year during the
term of this Lease, at BNSF's request and at no charge to BNSF (except as set
forth in Section 8(e) or (g)), commencing on the later of: (i) the date of
completion of the Initial Construction, or (ii) the date when capacity becomes
available at the desired location, and continuing for the entire term of this
Lease, the following fiber optic capacity, either over the entire length of the
Premises, or over any other Fiber Optic Facilities that are part of Pathnet's
fiber optic network within the area described in this Section 8(a), as
specified by BNSF, whether or not they are located on any of BNSF's Rail
Corridors:

                    (1) Each year during the first [***] years following
completion of Initial Construction (and each anniversary of the date of
completion of Initial Construction shall be referenced herein as "Anniversary
Date"), [***], or its equivalent, of digital transmission capacity for each
route mile of Pathnet's Fiber Optic Facilities constructed under this Lease;

                    (2) Each year, commencing on the [***] Anniversary Date,
until the [***] Anniversary Date, [***], or its equivalent, of digital
transmission capacity for each route mile of Pathnet's Fiber Optic Facilities
constructed under this Lease;

                    (3) Each year, commencing on the [***] Anniversary Date,
until the [***] Anniversary Date, [***], or its equivalent, of digital
transmission capacity for each route mile of Pathnet's Fiber Optic Facilities
constructed under this Lease;

                    (4) Each year, commencing on the [***] Anniversary Date,
until the [***] Anniversary Date, [***], or its equivalent, of digital
transmission capacity for each route mile of Pathnet's Fiber Optic Facilities
constructed under this Lease;


                                       6

<PAGE>   7
                    (5) Each year, commencing on the [***] Anniversary Date,
until the [***] Anniversary Date, [***], or its equivalent, of digital
transmission capacity for each route mile of Pathnet's Fiber Optic Facilities
constructed under this Lease;

                    (6) Each year, commencing on the [***] Anniversary Date,
until the [***] Anniversary Date, [***], or its equivalent, of digital
transmission capacity for each route mile of Pathnet's Fiber Optic Facilities
constructed under this Lease; and

                    (7) Each year, commencing on the [***] Anniversary Date,
until the [***] Anniversary Date, [***], or its equivalent, of digital
transmission capacity for each route mile of Pathnet's Fiber Optic Facilities
constructed under this Lease; and

                    (8) Each year, commencing on the [***] Anniversary Date,
until the [***] Anniversary Date, [***] miles, or its equivalent, of digital
transmission capacity for each route mile of Pathnet's Fiber Optic Facilities
constructed under this Lease.

          (b) The fiber optic capacity described in this Section 8 may be
specified by BNSF in any format then being provided by Pathnet on the Fiber
Optic Facilities on which BNSF requests fiber optic capacity. BNSF shall not be
entitled to the increases in capacity as set forth in Section 8(a) until, and
only to the extent that, the fiber optic capacity increases are required for
BNSF's uses, either on the Premises or on some other route in Pathnet's fiber
optic network within the area described in the first sentence of this Section
8(a). In addition, the miles of digital transmission capacity to which BNSF is
entitled may be specified by BNSF in its equivalent capacity, so that, for
example, if BNSF were entitled to [***] over a 2,000 mile route, this could be
[***] over [***] miles [***] each over [***], [***] over [***], or any
combination of the above totaling the capacity to which BNSF is entitled,
provided that the maximum cross-section at any point shall not exceed the lesser
of [***] of the then-available capacity on the Fiber Optic Facilities at that
location; or (ii) (I) prior to the [***] Anniversary Date, the equivalent of
[***]; (II) after the [***] Anniversary Date, and prior to the [***] Anniversary
Date, the equivalent of [***]; (III) after the [***] Anniversary Date, and prior
to the [***] Anniversary Date, the equivalent of [***]; (IV) after the [***]
[***] Anniversary Date, and prior to the [***] Anniversary Date, the equivalent
[***], and after the [***] Anniversary Date, and prior to the [***] Anniversary
Date, the equivalent of [***]. Pathnet shall have no obligation to install or
upgrade any of its digital telecommunications transmission facilities to provide
to BNSF any fiber optic capacity which at that time is not available on
Pathnet's Fiber Optic Facilities network. Pathnet shall have no obligation to
provide capacity at any multiplexed level below [***]. Pathnet will be
responsible for all costs associated with the creating, maintaining and
transporting the fiber optic capacity to be provided, including all optical
amplification and regeneration, and terminating the capacity at the multiplexor
or other optronic equipment at which the capacity is to be terminated, including
the cost of such terminating equipment. BNSF shall be responsible for all costs
of transport of the fiber optic capacity from the point of termination in the
shelter used by Pathnet to BNSF's desired point of termination.


                                       7

<PAGE>   8
     (c) The fiber optic capacity described in this Section 8 (including use of
the fibers addressed in Section 8(e)) may be utilized by BNSF and its Affiliates
(excluding any such Affiliate that competes in the telecommunications business)
for their respective internal communications only. The capacity made available
to BNSF by the terms of this Section 8 may not be sold, assigned, leased,
licensed, or otherwise made available to third-parties, or used in connection
with any telecommunications business. Notwithstanding the foregoing, BNSF is
discussing an agreement with a cellular telecommunications carrier that gathers
BNSF operational data, aggregates the BNSF operational data with its own
commercial cellular traffic, and delivers the BNSF operational data to BNSF
facilities. BNSF may allow the cellular telecommunications carrier or
partnership to use a portion of BNSF's retained fiber optic capacity as
described in this Section 8 in connection with the foregoing agreement. In
addition, BNSF may permit this one or other cellular telecommunications carriers
or partnerships to use any amount of additional fiber optic capacity as
described in this Section 8 for similar arrangements in the future. Any cellular
telecommunications carrier or partnership who utilizes BNSF's retained fiber
optic capacity in this way shall pay to Pathnet a charge equal to [***] of the
charge that Pathnet then is offering for sales of like capacity in like
markets."

     (c) In the event that Pathnet permanently discontinues telecommunications
services or capacity of which BNSF is using a portion, Pathnet will provide
sixty (60) days prior written notice to BNSF to permit BNSF to try to obtain
replacement capacity.

     (e)(1) Subject to the conditions set forth in this Section 8(e), BNSF may
require, in addition to the fiber optic capacity detailed in Section 8(b)
through 8(d), by notice in writing delivered to Pathnet no later than forty-five
(45) days after Pathnet's submission of Proposed Construction Plans respecting
any portion of the Fiber Optic Facilities, that Pathnet install [***] fibers in
those Fiber Optic Facilities, at Pathnet's sole cost, which [***] fibers shall
be an improvement to property of BNSF, from the Pathnet node site to a point
along the route of the Fiber Optic Facilities closest to BNSF's
telecommunications facility (hereinafter referenced as an "End Link"). These
[***] fibers shall be the same fiber type as that then being installed in those
Fiber Optic Facilities for Pathnet's own use, or to lease or sell capacity to
others, and, at Pathnet's sole discretion, may be contained within the same
cable sheath as Pathnet's fibers or within a separate cable sheath. Pathnet
shall be responsible for the maintenance of, and repair of these fibers for the
term of this Lease, so long as some fibers on the Premises, other than these
[***] fibers, are being maintained. Each End Link shall include a separate BNSF
handhole or manhole to be provided to BNSF, at Pathnet's sole cost, which shall
be an improvement to property of BNSF, to terminate and/or provide connection to
BNSF's telecommunications facility. Pathnet shall not be obligated to provide
fibers to BNSF in any End Link that is longer than [***] miles, nor shall
Pathnet be obligated to alter the planned route of the Fiber Optic Facilities,
except where BNSF has agreed in writing in advance to pay Pathnet's incremental
costs, including overhead, of extending any fibers more than [***] miles or
altering the planned route of

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<PAGE>   9
the Fiber Optic Facilities. If BNSF first required Pathnet to extend an End Link
after Commencement of Construction on the Rail Corridor segment where the End
Link is located, BNSF shall reimburse Pathnet for all such incremental costs,
including overhead. Pathnet shall perform such installation unless, in Pathnet's
reasonable judgment, performance thereof would materially adversely affect the
Fiber Optic Facilities or Pathnet's schedule for completion of Initial
Construction.

     (e)(2) Where BNSF requests an End Link on any corridor in BNSF's current
rail network, as defined in Section 8(a), Pathnet shall provide two 23-inch
racks, and space therefore, and adequate supporting electrical service, in
equipment shelters at terminal and junction sites on any BNSF Rail Corridor.
Where BNSF requests fiber optic capacity off of a corridor in BNSF's current
rail network, as defined in Section 8(a), Pathnet will make the requested
capacity available to BNSF at no charge, and BNSF shall be responsible to pay
the local exchange company to obtain the space, equipment and connection service
that BNSF requires.

     (f) In addition to the capacity to which BNSF is entitled under the terms
of this Section 8, BNSF shall have the right to purchase capacity on any portion
of Pathnet's network on terms no less favorable than Pathnet is then offering
for sales of like capacity and product over like distances in like markets.

            9.    Construction and Operation of Fiber Optic Facilities.

                      (a) (1) BNSF shall make available for inspection and
                  copying by Pathnet, at Pathnet's sole cost: (i) maps of BNSF's
                  Rail Corridor, and lists and/or center diagrams indicating the
                  approximate location and nature of all bridges and


                                       9
<PAGE>   10

                  locations of all tunnels, overpasses and other significant
                  railroad structures located on the Rail Corridor; (ii)
                  available engineering documents in BNSF's possession
                  (including profiles, lengths, internal diameter, etc.), that
                  relate to bridges, overpasses or tunnels on the Rail Corridor,
                  which Pathnet reasonably requests in connection with its
                  activities to Construct and Operate the Fiber Optic
                  Facilities; and (iii) maps, agreements (redacted to remove
                  confidential business terms) or other documents showing the
                  identity, location, rights and nature of other known users or
                  owners of portions of the Rail Corridor whose use, rights or
                  ownership Pathnet and BNSF reasonably determine would cause
                  title, possession or operational problems or cost to Pathnet
                  (including, without limitation, reversion rights of underlying
                  fee owners and, exclusivity rights of third parties); and (iv)
                  other such documentation or information reasonably requested
                  by Pathnet to assist Pathnet in its activities to Construct
                  and Operate the Fiber Optic Facilities and which, in the
                  opinion of BNSF, relates to or impacts upon the development of
                  Fiber Optic Facilities; all to the extent that (i) through
                  (iv) are readily and available from the records of BNSF or its
                  outside contractors charged with retaining such records, can
                  be located by BNSF in a reasonable search, and are not
                  confidential and proprietary to BNSF or third parties, and if
                  they are made available to Pathnet without determining what is
                  confidential or proprietary to BNSF, Pathnet shall keep such
                  information confidential and proprietary and shall not use it
                  for any purpose other than as set forth herein. The
                  availability of all such maps or documents shall not be
                  considered a guarantee or warranty that such maps or documents
                  are accurate or complete. The absence of markers, monuments or
                  maps indicating the present of subterranean facilities,
                  whether belonging to BNSF or otherwise, shall not constitute a
                  warranty or representation by BNSF that none exist. Pathnet
                  accepts this Lease with full cognizance of the potential
                  presence of the various claims, restrictions and physical
                  conditions described herein, acknowledging that Pathnet's
                  costs to Construct and Operate the Fiber Optic Facilities may
                  increase by reason thereof. Any failure by BNSF to provide
                  such documents shall not subject BNSF to any liability, costs,
                  expenses, damages, losses, or claims to Pathnet or any of the
                  Pathnet Parties, except to the extent of failures due to gross
                  negligence or willful misconduct.

                      (2) Pathnet recognizes that any BNSF documents supplied
                  by BNSF were not prepared for use as real estate title maps.
                  BNSF does not represent or suggest that the property lines and
                  Rail Corridor boundary lines shown on such documents are
                  accurate or that any other information contained on such
                  documents is correct.

                      (b) Prior to commencing construction of the Fiber Optic
                  Facilities, Pathnet, at its sole cost and risk, shall submit
                  to BNSF four sets of prints showing in detail the proposed
                  initial construction of all Fiber Optic Facilities on the
                  Premises, including every proposed element, item of equipment
                  and improvement included therein that Pathnet plans to locate
                  on the Premises, which prints shall be referenced herein as
                  "Proposed Construction Plans". Where Fiber Optic Facilities


                                       10
<PAGE>   11

                  extend over a route longer than 150 miles, Pathnet shall
                  submit Proposed Construction Plans to BNSF for each 150 mile
                  segment, as and when they are ready, and shall use its best
                  efforts to avoid any single submission of such Proposed
                  Construction Plans for a segment longer than 150 miles.

                      (c) (1) BNSF shall review the Proposed Construction
                  Plans, and may disapprove them, or propose changes, but any
                  disapproval or proposed change must be made in writing and
                  delivered to Pathnet within thirty (30) days of the date BNSF
                  receives such plans. Pathnet acknowledges that if BNSF does
                  not disapprove the Proposed Construction Plans, or propose any
                  changes to them, this does not constitute a determination by
                  BNSF that there are no design defects in such plans or that
                  Fiber Optic Facilities built in accordance with such plans
                  could be built or operated safely. If BNSF disapproves the
                  Proposed Construction Plans because it determines that
                  construction and/or maintenance of the Fiber Optic Facilities
                  likely would interfere with BNSF's rail operations or create a
                  safety hazard and that the Fiber Optic Facilities cannot be
                  located within BNSF's Rail Corridor for a specified distance,
                  and Pathnet then determines that the cost of locating its
                  Fiber Optic Facilities off of BNSF's Rail Corridors would be
                  significantly higher for Pathnet and so notifies BNSF, then
                  BNSF shall make reasonable efforts to work with Pathnet to
                  determine if there is a way to locate the Fiber Optic
                  Facilities somewhere on BNSF's Rail Corridor without
                  interfering with BNSF's rail operations or creating a safety
                  hazard. If BNSF disapproves all or any part of the Proposed
                  Construction Plans, BNSF, at the time of such disapproval,
                  shall provide to Pathnet a written explanation of the reasons
                  for disapproval and suggested cures, if any. Pathnet then
                  shall submit revised Proposed Construction Plans, which shall
                  be subject to the same review procedures just described. Once
                  the thirty (30) day period described above has expired and
                  BNSF has not disapproved the Proposed Plans (or the revised
                  Proposed Plans, if applicable), the same shall be the "Final
                  Construction Plans" which term shall also include any
                  subsequent modifications to the Plans as provided herein.
                  Pathnet shall not commence construction of the Fiber Optic
                  Facilities along any portion of the Rail Corridor in each
                  instance until it has received written notice from BNSF that
                  BNSF does not disapprove the Final Construction Plans.

                        (2) If at any time Pathnet desires to amend the Proposed
                  Construction Plans or the Final Construction Plans, Pathnet
                  must submit four sets of prints showing such amendment to BNSF
                  in the same manner described for submission of the Proposed
                  Construction Plans. If such amendment is not modified or
                  disapproved by BNSF in the manner specified for modification
                  or disapproval of Proposed Construction Plans, the Final
                  Construction Plans will be deemed as of such time to
                  incorporate such amendment

                   (d) In constructing the Fiber Optic Facilities, and with
                  respect to all entries onto the Rail Corridor by Pathnet and
                  the Pathnet Parties to Construct and




                                       11
<PAGE>   12

                  Operate the Fiber Optic Facilities, or for any other purpose,
                  Pathnet shall coordinate with BNSF, with the understanding
                  that BNSF's presence and activities on the Rail Corridor for
                  any purpose, except as limited by the Fiber Optic Access
                  Agreement, shall have priority over Pathnet's activities under
                  this Lease.

                        (e) The Construction Schedule shall be used by Pathnet
                  and BNSF to coordinate personnel, activities and train
                  movements. Pathnet shall amend the Construction Schedule, as
                  required, to reflect any and all schedule changes and shall
                  furnish promptly to BNSF any amended Construction Schedule.
                  BNSF may rely on the Construction Schedule to schedule flagmen
                  and other BNSF personnel whose duties require them to
                  accompany personnel constructing the Fiber Optic Facilities.

                        (f) If, at any time it appears to BNSF that BNSF's
                  tracks may be "Fouled" (defined in this Lease to mean the
                  presence of equipment and/or personnel of Pathnet or any of
                  the Pathnet Parties on a railroad track or within twenty-five
                  (25) feet of the centerline of any railroad track) in
                  connection with the exercise of Pathnet's rights under this
                  Lease, BNSF personnel may be provided, at BNSF's option, to
                  accompany Pathnet and/or any of the Pathnet Parties who may
                  Foul BNSF's tracks. Pathnet shall bear the entire cost
                  associated with such BNSF personnel, regardless of whether
                  such personnel are actually utilized in a particular case, and
                  Pathnet agrees promptly to pay all invoices for such personnel
                  that are submitted to it by BNSF. The failure of BNSF to
                  furnish such personnel shall not relieve Pathnet, or any of
                  the Pathnet Parties, of any obligations or liabilities it or
                  they otherwise have assumed hereunder.

                        (g) Pathnet, and all Pathnet Parties, who are or will be
                  involved in any activities or presence permitted under this
                  Lease on or near the Rail Corridor, shall comply with all
                  applicable BNSF safety rules and regulations, as set forth in
                  Exhibits "C" and "C-1" attached hereto. BNSF shall pay for any
                  such materials or safety training personnel (but Pathnet shall
                  pay any BNSF safety contractor's cost, including the cost of
                  any instructors); Pathnet shall pay salaries, any travel
                  expenses or other costs for Pathnet, and any and all such
                  Pathnet Parties, to receive such safety training.

                        (h) As promptly as possible, but in no event later than
                  six months after each segment of the Fiber Optic Facilities is
                  installed, Pathnet shall furnish to BNSF "As Built" Fiber
                  Optic Facilities drawings.

                        (i) During and in furtherance of completion of Initial
                  Construction, Pathnet and the Pathnet Parties, subject to
                  BNSF's prior written approval, may use, as required, and at no
                  additional charge, available portions of the Rail Corridor, as
                  identified by local BNSF personnel, for the purpose of
                  allowing Pathnet, or any of the Pathnet Parties, to erect, at
                  its sole cost and risk, temporary



                                       12
<PAGE>   13

                  structures and fences to protect Pathnet's material or
                  equipment necessary for the construction of the Fiber Optic
                  Facilities, including staging of construction activities and
                  storage of materials, provided that such structures and
                  fences: (i) shall not interfere with, or disrupt in any way,
                  other than in a manner approved in advance by BNSF, any
                  operations conducted by BNSF, or any activities of third
                  parties, on the Rail Corridor; and (ii) to the extent
                  reasonably feasible, shall be as shown and described in the
                  Final Construction Plans. Pathnet shall restore any land used
                  for such structures and fences substantially to its previous
                  condition before Initial Construction is complete, reasonable
                  wear and tear and casualty excepted, and shall remove all such
                  structures, fences, equipment and material placed thereon by
                  Pathnet, or any of the Pathnet Parties, before Initial
                  Construction is complete. In the event Pathnet does not comply
                  with the foregoing sentence, BNSF, following reasonable
                  advance notice to Pathnet, may take the actions specified in
                  that sentence, and Pathnet shall reimburse to BNSF all cost
                  incurred by BNSF in taking such actions.

                        (j) Subject to BNSF's approval and execution by the
                  applicable utility company of a BNSF standard form right of
                  entry permit, Pathnet may bring electrical power and other
                  utilities to the Fiber Optic Facilities. Pathnet shall make
                  its own arrangements, at its sole cost and risk, to obtain all
                  electrical power and other utilities or services necessary to
                  Construct and Operate the Fiber Optic Facilities, and Pathnet
                  shall indemnify, defend and hold BNSF harmless against any
                  liability to any utility or service company arising out of
                  utilities or services ordered or used by or on behalf of
                  Pathnet, except to the extent caused by the gross negligence
                  or willful misconduct of BNSF or its agents or contractors, or
                  any of their employees. Utilities and services needed by
                  Pathnet at each junction or repeater site shall be as shown
                  and described in the Final Construction Plans and shall be
                  part of Fiber Optic Facilities for purposes of this Lease. If
                  the location of such utilities or services serving the Fiber
                  Optic Facilities must be changed because of its interference
                  to BNSF railroad purposes or industrial development related to
                  railroad purposes, BNSF shall notify Pathnet and Pathnet
                  promptly shall relocate the affected Fiber Optic Facilities,
                  at Pathnet's sole cost, in a manner satisfactory to BNSF.
                  Power sources installed by Pathnet shall be part of the
                  Initial Construction.

                        (k) Pathnet, at its sole cost and risk, shall furnish
                  all materials, supervision, labor, parts, components,
                  equipment and structures necessary to Construct and Operate
                  the Fiber Optic Facilities, or any part thereof, in accordance
                  with this Lease. Any and all work by Pathnet and/or a Pathnet
                  Party under the authority of this Lease shall be done in a
                  good and workmanlike manner, in conformity with the Final
                  Construction Plans, and shall comply with all applicable
                  engineering, safety, and other statutes, laws, ordinance,
                  regulations, rules, codes, orders or specifications of any
                  public body or authority having jurisdiction over the Fiber
                  Optic Facilities or BNSF's rail operations, including,



                                       13
<PAGE>   14

                  but not limited to, the Federal Communications Commission and
                  the Federal Railroad Administration.

                        (l) All installations by Pathnet and/or a Pathnet Party
                  under the authority of this Lease must meet or exceed
                  applicable specifications of the public authority of the state
                  in which the installation is located and must be in compliance
                  with all existing federal, state or local laws, ordinances,
                  and regulations. In no case shall any part of the Fiber Optic
                  Facilities be located in a manner that will interfere with the
                  presence or activities of BNSF, or any third parties acting
                  within their rights on the Rail Corridor as they exist on the
                  date of this Lease. The manner of, and the equipment and
                  devices to be used for, any installation, relocation or
                  removal of the Fiber Optic Facilities, shall be reviewed in
                  advance by BNSF, as set forth herein.

                        (m) Fiber Optic Facilities may be installed by Pathnet,
                  at its sole cost and risk, on bridges or other water crossings
                  on the Rail Corridor by attachment to BNSF's fixed or movable
                  bridges or crossing structures, as available, as agreed by
                  BNSF and Pathnet, as shown in the Final Construction Plans.

                        (n) Installation of Fiber Optic Facilities under public
                  roadways shall be at Pathnet's sole cost and risk, at a
                  location and depth as agreed to by BNSF, as shown on the Final
                  Construction Plans.

                        (o) Installation of Fiber Optic Facilities crossing over
                  or under other existing facilities in the Rail Corridor shall
                  be located and installed, at Pathnet's sole cost and risk, in
                  accordance with conditions set forth in this Section 9, and
                  applicable requirements of the owner of each such facility.
                  If, in the course of any activity that Pathnet is authorized
                  to undertake under the terms of this Lease, any changes in any
                  pipelines, sewers, conduits, fences, power, signal or
                  communication lines or other utility, facility or Railroad
                  Facilities is necessary (either temporary or permanent), such
                  change shall require prior review by BNSF, and a letter from
                  BNSF indicating that it does not disapprove such change, and
                  all other necessary approvals from third parties. Pathnet
                  shall indemnify, defend and hold BNSF harmless against all
                  claims from any third party relating to any such activity.

                        (p) All cranes, lifts, drilling equipment, or other
                  machinery that is to be operated in the vicinity of any Rail
                  Facilities, electric transmission lines or other facilities in
                  connection with Initial Construction or any other activity
                  that Pathnet is authorized to undertake under the terms of
                  this Lease, shall be electrically grounded in a manner
                  reviewed by, and not disapproved by, BNSF. Pathnet
                  acknowledges that if BNSF does not disapprove such plans this
                  does not constitute a determination by BNSF that such plans or
                  activities are safe. All personnel of Pathnet and any of the
                  Pathnet Parties that are operating such cranes, lifts,
                  drilling equipment, or other machinery shall have appropriate
                  and sufficient



                                       14
<PAGE>   15

                  experience in operating of the machinery being used, and
                  Pathnet shall be prepared to certify the extent of this
                  experience upon request by BNSF.

                        (q) If Pathnet, or any of the Pathnet Parties, acting
                  under the authority granted by this Lease, discovers any
                  scientific or historic artifacts, Pathnet immediately shall
                  notify BNSF of such discovery and shall protect such artifacts
                  until they are identified and removed by the appropriate
                  authorities.

                        (r) BNSF shall have the right to verify by inspection,
                  at the sole cost of Pathnet, that the location of the work and
                  the materials constituting the Initial Construction, or used
                  operation of the Fiber Optic Facilities, are in compliance
                  with the Final Construction Plans. BNSF shall give Pathnet
                  reasonable notice of such inspections, and Pathnet, at its
                  option, may designate a representative to accompany BNSF's
                  representative on such inspections. If, following an
                  inspection, BNSF reasonably determines that Pathnet is
                  conducting activities that do not comply with the approved
                  Final Construction Plans, the parties hereto shall meet
                  promptly to discuss the situation and determine a remedy
                  satisfactory to BNSF. If BNSF is not satisfied with the remedy
                  selected at such meeting, and its subsequent implementation,
                  Pathnet's rights to Construct and Operate Fiber Optic
                  Facilities shall be suspended entirely until the parties have
                  settled on a remedy that is satisfactory to BNSF. The
                  provisions of Section 7 shall apply to any suspension of work
                  pursuant to this Section.

                        (s) BNSF's expenses for any work performed for or at the
                  expense of Pathnet pursuant to the terms of this Lease shall
                  be paid by Pathnet promptly upon Pathnet's receipt of each
                  itemized bill therefor. Expenses so billed by BNSF shall be
                  only those attributable to the work performed and shall
                  include, without limitation, cost of labor (whether performed
                  by BNSF or a contractor of BNSF) and supervision, necessary
                  travel or transportation expenses, lodging, meals, equipment
                  rental, materials, and any freight and handling charges on
                  materials used, plus standard additives A list of standard
                  additives then in effect will be provided to Pathnet with any
                  billing containing such activities.

                        (t) Pathnet, at its sole cost and risk: (i) shall secure
                  and maintain in effect all federal, state, and local permits,
                  licenses, platting, subdivisions, and/or zoning approvals or
                  any other land use requirement that is required to Construct
                  and Operate the Fiber Optic Facilities, including, without
                  limitation, crossing, zoning, building, health, environmental,
                  and communication permits and licenses, and Pathnet, at its
                  sole cost and risk, shall satisfy any and all conditions
                  required to obtain, maintain and comply with any required
                  permit, license or zoning approval or any other land use
                  requirement; and (ii) shall indemnify, defend and hold
                  harmless BNSF from and against payment of the cost therefor,
                  and against any fines or penalties that may be levied for
                  failure to procure, maintain or to comply with any such
                  permits, licenses and/or zoning, or any other land use
                  requirement as well as any remedial costs incurred by BNSF in
                  curing any such


                                       15
<PAGE>   16

                  failure. BNSF shall cooperate with Pathnet in securing and
                  maintaining any such permits or licenses, and Pathnet shall
                  reimburse any reasonable out-of-pocket costs of BNSF in
                  providing such cooperation..

                        (u) Any environmental impact statements required by any
                  governmental agency in connection with any activity of Pathnet
                  to Construct and Operate the Fiber Optic Facilities shall be
                  prepared by Pathnet at Pathnet's sole cost and risk, and
                  Pathnet, at its sole cost and risk, shall comply with any
                  conditions required by any applicable government authority in
                  connection with, or following from, any environmental impact
                  statement.

                        (v) BNSF shall cooperate with Pathnet, as requested by
                  Pathnet, at no out-of-pocket cost to BNSF, in Pathnet's
                  efforts to obtain and maintain any permits, licenses or
                  approvals of government agencies or authorities, or any
                  approvals of any necessary third parties, for the use of any
                  structures or facilities (including streets, roads or utility
                  poles) along portions of the Rail Corridor. The provisions of
                  this paragraph will not be deemed to require BNSF to expend
                  significant internal resources.

            10.   Entry Notice.

                        (a) During progress of the Initial Construction, Pathnet
                  shall give BNSF at least five days' written notice before
                  initial entry by Pathnet, or any of the Pathnet Parties, upon
                  any portion of the Rail Corridor.

                        (b) After completion of Initial Construction, any entry
                  by Pathnet or any Pathnet Party onto the Rail Corridor that
                  does not constitute Routine Maintenance and Operation (defined
                  later herein) of the Fiber Optic Facilities, or is not related
                  to an Emergency (defined later herein) shall require: (i)
                  advance written notice from Pathnet to BNSF not less than ten
                  days prior to such planned entry, such notice to specify the
                  purpose of the entry; (ii) if entry involves any new
                  construction, reconstruction, or removal of Fiber Optic
                  Facilities, four (4) sets of prints showing in detail such
                  proposed new construction, reconstruction, or removal; and
                  (iii) approval by BNSF, which approval shall not be
                  unreasonably withheld or delayed, taking in account the nature
                  of the proposed entry. As used herein, "Routine Maintenance
                  and Operation" shall mean maintenance and operation by Pathnet
                  and/or a Pathnet Party of the Fiber Optic Facilities that does
                  not require any: (i) excavation of soil that could alter or
                  disturb, or threaten the support of, or ability to use, any
                  Rail Facility; (ii) use of heavy machinery within 50 feet of
                  any railroad track; or (iii) an activity or presence which
                  results in a Fouled railroad track. As used herein,
                  "Emergency" shall mean that service on the Fiber Optic
                  Facilities has been interrupted or significantly disrupted or
                  such interruption is reasonably likely, or that there is a
                  material adverse threat to the integrity of Pathnet's fiber
                  optic network, in circumstances that make it



                                       16
<PAGE>   17

                  impractical for Pathnet or any Pathnet Party to give BNSF
                  normal advance written notice of entry onto BNSF's Rail
                  Corridor.

                        (c) During Routine Maintenance and Operation, Pathnet
                  and/or any Pathnet Party may enter the Rail Corridor without
                  notice to BNSF, for the sole purpose of Routine Maintenance
                  and Operation; provided, however, that: (i) if any entry for
                  such purpose is likely to result in a Fouled railroad track,
                  Pathnet shall give BNSF written notice of the places where and
                  the manner in which entry is required not less than two (2)
                  days, and not more than seven (7) days, prior to such entry;
                  and (ii) without BNSF's prior consent, which shall not be
                  unreasonably withheld, neither Pathnet nor any Pathnet Party
                  shall enter the Rail Corridor at any place where BNSF
                  previously has disapproved entry.

                        (d) In the event of an Emergency, Pathnet and/or any
                  Pathnet Party may enter the Rail Corridor without notice to
                  BNSF, for the sole purpose of dealing with the Emergency;
                  provided, however, that: (i) if any entry for such purpose is
                  likely to result in a Fouled railroad track, Pathnet shall
                  obtain verbal or written approval from BNSF prior to such
                  entry, promptly followed by written confirmation of such
                  approval, which may be provided within 24 hours after Pathnet
                  has addressed the Emergency; (ii) if any entry for such
                  purpose is likely to require the excavation of soil that could
                  alter or disturb, or threaten the support of or ability to
                  use, any Rail Facility, or would involve the use of heavy
                  machinery within 50 feet of any railroad track, Pathnet shall
                  give BNSF verbal or telephonic notice of the places where, and
                  the manner in which, entry is required prior to such entry,
                  promptly followed by written confirmation which shall be
                  obtained within 24 hours after Pathnet has addressed the
                  Emergency. and (iii) without BNSF's prior consent, which shall
                  not be unreasonably withheld, neither Pathnet nor any Pathnet
                  Party shall enter the Rail Corridor at any place where BNSF
                  previously has disapproved entry. Both parties acknowledge
                  that an Emergency involving a derailment or other similar
                  situation could cause significant damage to both parties, and
                  that both parties will need to respond promptly and
                  effectively to the situation. Subject to (i), (ii) and (iii)
                  above, in the event of an Emergency involving a derailment or
                  other similar situation, BNSF agrees that it will not prohibit
                  Pathnet from responding to the situation as appropriate to
                  repair or protect the Fiber Optic Facilities, provided that
                  Pathnet does not interfere with BNSF's rail operations or
                  related activities. The parties will cooperate with one
                  another to enable each party to take appropriate response
                  action as promptly and effectively as possible.

            11.   Maintenance of Premises and Fiber Optic Facilities. BNSF shall
not be responsible for maintenance of any Fiber Optic Facilities, or for
clearing or removal of trees, shrubs, plants, ice, snow or debris from the
Premises. Pathnet shall be responsible to remove from the Rail Corridor any
debris resulting from any of the activities of Pathnet or any of the Pathnet
Parties acting under the authority of this Lease.



                                       17
<PAGE>   18

            12.   Track Support: Materials Storage.

                  (a) During any work by Pathnet or any of the Pathnet Parties
            pursuant to this Lease, Pathnet shall ensure that all tracks,
            supporting structures and roadbed of BNSF is supported in such
            manner as is necessary for the safe operation of BNSF without any
            slower speed or other train operating restrictions and, upon
            completion of such work, Pathnet shall ensure that all such tracks,
            supporting structures, and the roadbed are returned to their
            pre-existing condition, all at Pathnet's sole cost.

                  (b) Except as expressly set forth in the Final Construction
            Plans, Pathnet shall not store or temporarily place any goods,
            materials, or equipment on the Rail Corridor: (i) near a highway or
            private grade crossing in such a manner as to interfere with the
            sight distance of anyone approaching such crossing; (ii) within
            fifteen feet of the end of any tie in any railroad track; or (iii)
            within such greater distance as required by an applicable government
            authority. Notwithstanding any other provision in this Lease,
            Pathnet shall not store or temporarily place fuel or any Hazardous
            Substance (as defined later herein) on the Rail Corridor, other than
            as may be approved in writing in advance by BNSF. If Pathnet
            knowingly discovers any Hazardous Substances on the Premises,
            Pathnet will promptly notify BNSF, suspend or relocate activities
            that would disturb the Hazardous Substance, and permit BNSF to take
            appropriate actions. BNSF will respond promptly to any such
            situation.

            13.   Facility Location Signs. Pathnet, at its sole cost and risk,
shall furnish, erect, and thereafter maintain signs showing the location of all
underground Fiber Optic Facilities. The size, form, color, text, location, and
spacing of such signs shall be subject to advance review by BNSF, and such signs
shall be in conformance with standard industry practices and shall be considered
part of the Fiber Optic Facilities.

            14.   Relocations.

                  (a) If BNSF determines that the location of any of the Fiber
            Optic Facilities must be changed due to either: (i) relocation or
            placement of any Rail Facilities; (ii) rail operating improvements
            for BNSF (or for any other party offering rail service in the Rail
            Corridor via rights granted or conveyed by BNSF); (iii) locating or
            modifying a rail customer's facilities, buildings or other
            improvements along BNSF's rail route, or locating or modifying any
            facilities, buildings or other improvements for railroad purposes or
            industrial development related to railroad purposes; or (iv) any
            reason beyond the control of BNSF, BNSF shall notify Pathnet of such
            plans and shall use reasonable efforts to secure an alternative
            location for the Fiber Optic Facilities within the Rail Corridor, in
            light of BNSF's business assets, plans and activities and the rights
            of third parties in the Rail Corridor, or to provide Pathnet with an
            opportunity to protect its Fiber Optic Facilities if Pathnet may do
            so without interference with the situation requiring relocation;
            provided however, BNSF shall not be obligated to spend any money, or
            incur any



                                       18
<PAGE>   19

            liabilities, to secure such an alternative location. If such
            alternative location is found on the Rail Corridor, Pathnet shall
            move the affected Fiber Optic Facilities to such alternative
            location, at Pathnet's sole cost and risk, as soon as practicable.
            If a location for Fiber Optic Facilities cannot be found on the Rail
            Corridor, Pathnet shall move the affected Fiber Optic Facilities off
            of the Rail Corridor as soon as practicable, at Pathnet's sole cost
            and risk.

                  (b) In the event BNSF desires that Pathnet also move certain
            Rail Facilities (excluding tracks and track structures)
            simultaneously with moving its Fiber Optic Facilities, BNSF shall so
            notify Pathnet in writing, and Pathnet shall move such Rail
            Facilities and shall invoice BNSF for the reasonable, actual
            incremental costs, including reasonable overhead costs, that are
            incurred by Pathnet in moving such Rail Facilities.

                  (c) If BNSF desires to relocate any of the Fiber Optic
            Facilities in order to accommodate a third party (other than as set
            forth in Section 14(a)), BNSF shall so notify Pathnet, and Pathnet
            promptly thereafter shall submit to BNSF a reasonable, detailed,
            itemized estimate, including reasonable contingencies ("Estimate")
            of its anticipated reasonable actual costs to relocate such Fiber
            Optic Facilities (including reasonable overhead costs not to exceed
            ten percent (10%) of actual costs). Upon receiving from BNSF fifty
            percent of the amount of the Estimate, Pathnet shall proceed, as
            expeditiously as feasible under the circumstances, to relocate those
            Fiber Optic Facilities at a cost not to exceed one hundred ten
            percent (110%) of the Estimate. Upon completion of such relocation,
            and submission to BNSF of invoices documenting all costs thereof,
            BNSF promptly shall pay the balance of such costs to Pathnet.

                  (d) Pathnet acknowledges that BNSF's ownership rights in all
            or certain portions of the Rail Corridor may terminate, or revert,
            if BNSF ceases to use the Rail Corridor for rail transportation
            purposes, or, in some cases if BNSF uses the Rail Corridor for a
            purpose inconsistent with rail transportation purposes, or for other
            reasons, such as termination of franchise rights, and that if this
            occurs, Pathnet might be required either to relocate its Fiber Optic
            Facilities or acquire from the appropriate party the right to
            continue to use the Fiber Optic Facilities. BNSF shall have no
            obligation not to abandon rail service over all or any portion of
            the Rail Corridor, no obligation not to use the Rail Corridor for a
            purpose inconsistent with rail transportation purposes, and no
            obligation to extend the term of BNSF's franchise rights or
            ownership rights in the Rail Corridor.

            15.   Condemnation. In the event that any portion of the Premises
becomes the subject of condemnation proceedings, BNSF shall make reasonable
efforts to notify Pathnet promptly. Pathnet's interest in the personal property,
improvements, and facilities comprising the Fiber Optic Facilities shall be
valued separately from BNSF's ownership interest in the Fiber Optic Facilities
and the Premises, and BNSF and Pathnet shall seek to have any condemnation
award, or sale in lieu of condemnation, apportioned between Pathnet and BNSF
based on the relative value of their specific ownership interests in the Fiber
Optic Facilities and the Premises.



                                       19
<PAGE>   20

            16.   Conveyance of Rail Corridor. In the event BNSF conveys all or
any portion of the Rail Corridor, in circumstances not covered by Section 14 or
Section 15 of this Lease, such conveyance shall be subject to any existing
rights of Pathnet under this Lease and the Fiber Optic Access Agreement, to the
extent permitted by applicable laws and agreements entered into prior to the
date of this Lease.

            17.   Compliance with Laws. Pathnet, in exercising any and all
rights under this Lease, shall comply with all applicable laws, regulations,
ordinance, rules, decisions and orders ("Laws") applicable to Pathnet and/or the
Fiber Optic Facilities, or resulting from the exercise of Pathnet's rights, and
shall have the sole responsibility for all costs and risks associated with such
compliance. Pathnet shall indemnify, defend and hold harmless BNSF against any
claims, damages, costs, fines or penalties arising in any way from Pathnet's
breach of this Section 17.

            18.   Liability: Indemnification. PATHNET HEREBY RELEASES BNSF FROM,
AND AGREES TO INDEMNIFY, DEFEND, PROTECT, AND HOLD BNSF HARMLESS AGAINST, ANY
AND ALL CLAIMS, SUITS, JUDGMENTS, LIABILITIES AND EXPENSES (INCLUDING, BUT NOT
LIMITED TO, REASONABLE ATTORNEYS' FEES) ARISING OUT OF OR RELATED TO:

            (1)   ANY LOSS OF AND/OR DAMAGE TO THE REAL OR PERSONAL PROPERTY OF
BNSF, PATHNET OR THIRD PARTIES AND ANY LOSS AND/OR DAMAGE ON ACCOUNT OF INJURY
TO, OR DEATH OF, ANYONE, CAUSED BY OR GROWING OUT OF PATHNET'S, OR ANY PATHNET
PARTY'S PRESENCE OR ACTIVITIES ON OR NEAR THE RAIL CORRIDOR, REGARDLESS OF ANY
NEGLIGENCE OF BNSF OR ANY PARTY THEN PERFORMING AS A CONTRACTOR OR AGENT OF
BNSF, EXCEPT TO THE EXTENT (AND ONLY TO THE EXTENT) THAT SUCH LOSS OR DAMAGE IS
PROXIMATELY CAUSED BY THE GROSS NEGLIGENCE OR WILLFUL MISCONDUCT OF BNSF OR SUCH
CONTRACTOR OR AGENT OF BNSF;

            (2)   (i) EXCEPT IN CONNECTION WITH THE FIBERS AND CAPACITY TO BE
PROVIDED TO BNSF, SERVICE INTERRUPTION, CESSATION, OR UNRELIABILITY OF THE FIBER
OPTIC FACILITIES CAUSED BY ANY PERSON, REGARDLESS OF ANY NEGLIGENCE OF BNSF OR
ANY PARTY THEN PERFORMING AS A CONTRACTOR OR AGENT OF BNSF, EXCEPT TO THE EXTENT
(AND ONLY TO THE EXTENT) THAT SUCH SERVICE INTERRUPTION, CESSATION OR
UNRELIABILITY WAS CAUSED BY THE GROSS NEGLIGENCE OR WILLFUL MISCONDUCT OF BNSF
OR SUCH CONTRACTOR OR AGENT OF BNSF, OR (ii) EXCEPT IN CONNECTION WITH THE
FIBERS AND CAPACITY TO BE PROVIDED TO BNSF, LIBEL, SLANDER, INFRINGEMENT OR
COPYRIGHT, OR UNAUTHORIZED USE OF ANY TRADEMARK, TRADE NAME, OR SERVICE MARK,
ARISING OUT OF THE MATERIAL, DATA, INFORMATION OR OTHER CONTENT TRANSMITTED OR
RECEIVED OVER THE FIBER OPTIC FACILITIES, IN EACH CASE REGARDLESS OF WHETHER
SUCH CLAIMS, SUITS, JUDGMENTS, OR LIABILITIES ARISE FROM NEGLIGENCE, ACTIONS, OR
INACTION OF BNSF, OR ANY PARTY USING THE RAIL CORRIDOR WITH PERMISSION OF BNSF;
AND



                                       20
<PAGE>   21

            (3)   ANY BREACH OF THE TERMS OF THIS LEASE BY PATHNET OR ANY OF THE
PATHNET PARTIES.

            WITHOUT LIMITATION OF ANY OF THE FOREGOING, PATHNET HEREBY AGREES TO
INDEMNIFY, DEFEND, PROTECT AND HOLD BNSF HARMLESS FROM AND AGAINST ANY AND ALL
LOSS, DAMAGE, COST AND EXPENSE SUSTAINED, SUFFERED, OR INCURRED BY BNSF AS A
RESULT OF THE EXISTENCE OF ANY HAZARDOUS SUBSTANCE WITHIN THE RAIL CORRIDOR TO
THE EXTENT CAUSED BY, CONTRIBUTED TO, EXPOSED BY OR AGGRAVATED BY PATHNET OR ANY
PATHNET PARTY. HAZARDOUS SUBSTANCE AS USED HEREIN SHALL MEAN MATERIAL OR
CONTAMINATION IN VIOLATION OF ANY APPLICABLE ENVIRONMENTAL LAW, ORDER, DECISION
OR REGULATION.

            19.   Insurance.

                  (a) Pathnet, prior to entering onto the Rail Corridor shall
            procure the following insurance, covering all of the work and
            services to be performed hereunder by Pathnet, which shall remain in
            effect for so long as such party has any personnel, property or
            facilities on, or having a right to be on, the Rail Corridor, at
            their sole cost:

                      (1) Workers' Compensation and Employers Liability
                  Insurance in an amount of at least $1,000,000, covering the
                  entire liability of Pathnet, as determined by the compensation
                  laws of the State in which the work is performed, but if
                  optional under State law the insurance must cover all
                  employees anyway, or the federal workmen's compensation laws
                  as applicable. THE CERTIFICATE MUST CONTAIN A SPECIFIC WAIVER
                  OF THE INSURANCE COMPANY'S SUBROGATION RIGHTS AGAINST THE
                  BURLINGTON NORTHERN AND SANTA FE RAILWAY COMPANY.

                      (2) Commercial General Liability insurance and
                  umbrella liability insurance covering liability, including but
                  not limited to Public Liability, Personal Injury, Property
                  Damage, and Contractual Liability with combined coverage of at
                  least $21,000,000 per occurrence and a general aggregate of at
                  least $21,000,000. Where explosion, collapse, or underground
                  hazards are involved, the X, C and U exclusions must be
                  removed from the policy;

                      (3) Automobile Liability insurance, including bodily
                  injury and property damage, with coverage of at least
                  $1,000,000 combined single limit or the equivalent covering
                  any and all vehicles owned, used or hired by Pathnet;

                      (4) All Risk Property Damage insurance covering all
                  of the property of Pathnet on a replacement cost basis
                  including property in their care, custody or control and first
                  party pollution clean up. The first party pollution clean up
                  shall include, at a minimum, debris removal and cost of clean
                  up on a named perils




                                       21
<PAGE>   22

                  basis. Such insurance shall contain a waiver of subrogation in
                  favor The Burlington Northern and Santa Fe Railway Company.

                      (5) Pollution Liability coverage in an amount of not
                  less than $2,000,000 per occurrence and in the aggregate and
                  shall include coverage for: (a) bodily injury, sickness,
                  disease, mental anguish or shock sustained by any person,
                  including death; (b) property damage including physical injury
                  to or destruction of tangible property including the resulting
                  loss of use thereof, clean up costs, and the loss of use of
                  tangible property that has not been physically injured or
                  destroyed; and (c) defense including loss adjustment costs,
                  charges and expenses incurred in the investigation adjustment
                  or defense of claims for such compensatory damages.

                      (6) If Pathnet requires disposal of any hazardous or
                  non-hazardous materials off of their property, Pathnet shall
                  utilize only a fully licensed and qualified disposal company.

                      (7) Railroad Protective Liability insurance naming The
                  Burlington Northern and Santa Fe Railway Company as the Named
                  Insured with coverage of at least $5,000,000 per occurrence
                  and $10,000,000 in the aggregate. Coverage shall be issued on
                  a standard ISO for CG 00 35 01 96 and endorsed to include ISO
                  for CG 28 31 10 93 and the Limited Seepage and Pollution
                  Endorsement.

            All insurance shall be placed with insurance companies licensed to
            do business in the States in which the work is to be performed, and
            with a Best's Insurance Guide Rating of A- and Class VII, or better.

            If any work is to be performed within 50 feet of railroad property,
            then the insurance must provide for coverage of incidents occurring
            within fifty (50) feet of railroad property, and any provision to
            the contrary (including any limitation regarding the definition of
            an insured contract) in the insurance policy must be specifically
            deleted.

            To the extent obtainable, with respect to any incident on or along
            the Rail Corridor, in all cases except for Workers' Compensation,
            the certificate must specifically state that "THE BURLINGTON
            NORTHERN AND SANTA FE RAILWAY COMPANY IS AN ADDITIONAL INSURED." The
            Additional Insured endorsement shall, at a minimum, include coverage
            for the general supervision performed by BNSF.

            Any coverage afforded BNSF, the Certificate Holder, as an Additional
            Insured shall apply as primary and not excess to any insurance
            issued in the name of BNSF.

                  (b) Before commencing any work hereunder, Pathnet shall
            furnish to BNSF, Certificate of Insurance on the form prescribed by
            BNSF, evidencing the issuance to Pathnet of the policies of
            insurance providing the types of insurance and limits of liability
            prescribed above, and amending the cancellation clause to certify
            that BNSF shall be



                                       22
<PAGE>   23

            given not less than 30 days' written notice prior to any material
            change, substitution or cancellation prior to normal expiration
            dates. Cancellation or expiration of any of said policies of
            insurance shall not preclude BNSF from recovery thereunder for any
            liability arising under this Agreement.

            If any coverage is purchased on a "claims made" basis, Pathnet
            hereby agrees to maintain coverage in force for a minimum of three
            years after expiration, cancellation or termination of this
            contract. Pathnet shall provide evidence annually of such coverage
            as required hereunder.

                  (c) Pathnet Parties shall procure and maintain insurance as
            outlined in Exhibit C-1.

                  (d) It is mutually understood and agreed that the purchase of
            insurance as herein provided shall not in any way limit the
            liability of the Pathnet or Pathnet Parties to BNSF, as herein set
            forth.

            20.   Liens.

                  (a) In the event that any BNSF property becomes subject to any
            mechanics' or materialmen's lien, or other construction or
            supplier's lien or encumbrance chargeable to or through Pathnet or
            any of the Pathnet Parties as a result of a failure to pay. Pathnet
            promptly, and in any event within ten days, shall cause such lien or
            encumbrance to be discharged or released of record (by payment,
            posting of bond, court deposit or other means), without cost to
            BNSF, and shall indemnify and hold harmless BNSF against all costs
            (including reasonable attorneys' fees) incurred in connection with
            such lien or encumbrance. If any such lien or encumbrance is not so
            discharged and released, BNSF may pay or secure the release or
            discharge thereof, at the expense of Pathnet, after first giving
            five days' advance notice of its intention to do so. Pathnet
            acknowledges that: (i) all or portions of the Rail Corridor are
            subject to the liens of one or more of BNSF's various mortgages;(ii)
            BNSF from time to time may place other liens or mortgages on the
            Rail Corridor and (iii) the discharge or release of record of the
            current or future liens and mortgages from the Rail Corridor is not
            required by this Section, provided however, that any such future
            liens or mortgages shall be subject to Pathnet's rights under this
            Lease.

                  (b) Nothing herein shall preclude either Pathnet or BNSF from
            contesting of any lien or other encumbrance.

            21.   Liaison, Dispute Resolution and Arbitration.

                  (a) Not later than thirty days after the date of this Lease,
            BNSF and Pathnet each shall send a letter to the other, pursuant to
            Section 28 hereof, designating individuals as points of contact at
            the following levels: corporate officer for overall decision-making,
            corporate officer for dispute resolution; contact person for
            day-to-day corporate contact and liaison; contact person for
            engineering and project management; contact person for



                                       23
<PAGE>   24

            field construction; contact person for daily operations and
            maintenance; and contact person for disaster operations on a
            twenty-four (24) hour basis. The same individual may be designated
            for one or more of the foregoing positions, and either BNSF or
            Pathnet may change the name of any designated officer or contact
            person at any time by so informing the other in writing.

                  (b) It is the intent of the parties hereto that any dispute
            which may arise between them be resolved as quickly and as
            informally as possible. When quick and informal resolution of any
            dispute is not possible, the issues in dispute shall be referred to
            the two corporate officers designated for dispute resolution
            pursuant to this Section 21, who shall make a reasonable attempt to
            settle the dispute.

                  (c) The parties hereto agree to waive any rights that either
            may have to a remedy in a court of law or in a court of equity
            arising out of this Lease, and to submit any dispute arising under
            the Lease, and not settled pursuant to Section 21(b) hereof, to
            binding arbitration in accordance with this Section 21.
            Notwithstanding the foregoing, either party shall have the right to
            pursue preliminary equitable relief in connection with this Lease,
            or to pursue appropriate legal or equitable remedies in support of a
            decision rendered in arbitration.

                  (d) The parties hereto agree that one of the remedies
            available to the arbitrator(s) for any substantial breach of this
            Agreement shall be specific performance, and that an award of
            specific performance by an arbitrator or arbitrators may be enforced
            in a court of law or equity.

                  (e) Any arbitration under this Agreement shall be conducted in
            accordance with the Commercial Rules of the American Arbitration
            Association and shall be conducted by an arbitrator, and said
            arbitration shall be conducted by a panel of three (3) arbitrators,
            one to be selected by BNSF, one to be selected by Pathnet, and one
            to be selected by the two designated arbitrators. Discovery shall be
            conducted in accordance with the Federal Rules of Civil Procedure

                  (f) All costs, fees and expense charged by the arbitrator(s)
            and other neutral third parties retained by mutual agreement of
            Pathnet and BNSF in any arbitration conducted pursuant to this
            Section 21 shall be shared equally by Pathnet and BNSF, unless
            apportioned otherwise by the arbitrators.

            22.   Representations and Warranties.

                  (a) By executing this Lease, BNSF represents and warrants the
            following facts:

                      (1) BNSF has the full right and authority to enter
                  into and perform this Lease, and by entering into and
                  performing this Lease, BNSF is not in violation of its charter
                  or by-laws, or any Laws or agreement by which it is bound or
                  to which it is subject; it being understood, however, that
                  this warranty does not



                                       24
<PAGE>   25

                  constitute a warranty, express or implied, that BNSF has
                  sufficient rights in the Rail Corridor to permit Pathnet to
                  Construct and Operate the Fiber Optic Facilities; and

                           (2) The execution, delivery and performance of this
                  Lease by BNSF has been duly authorized by all requisite
                  corporate action, that the signatory for BNSF hereto is
                  authorized to sign this Lease and bind BNSF to its terms.

                  (b)      By executing this Lease, Pathnet represents and
                  warrants:

                           (1) Pathnet has the full right and authority to enter
                  into and perform this Lease and by entering into and
                  performing this Lease, Pathnet is not in violation of its
                  charter or by-laws, or any Laws or agreement by which it is
                  bound or to which it is bound or to which it is subject;

                           (2) The execution, delivery and performance of this
                  Lease by Pathnet has been duly authorized by all requisite
                  corporate action, that the signatory for Pathnet hereto is
                  authorized to sign this Lease and bind Pathnet to its terms;
                  and

                           (3) Pathnet has the financial capability to fulfill
                  all of its obligations under this Lease.


            23.   Limitation on Damages for Breach of this Lease. Damages that
may be recovered for breach of this Lease shall not include any indirect,
consequential, special or punitive damages, or lost profits, or the cost of
Pathnet building Fiber Optic Facilities at a different location than it
originally planned.


            24.   Recordings, Taxes and Other Charges.

                  (a) Except as provided in this Section 24, Pathnet shall pay:
            (i) all transfer taxes, documentary stamps, recording costs or fees,
            or any similar expense in connection with this Lease and/or the
            recording or filing of a Memorandum of Lease for this Lease (which
            memorandum shall be in a form mutually agreeable between the parties
            and the recording of a Memorandum of Lease shall occur only by
            mutual agreement by the parties); and (ii) any and all taxes
            (including but not limited to transfer, sales, use, and property
            taxes), levies, excises, assessments and charges (collectively,
            "Taxes"), including any penalties and/or interest thereon, levied or
            assessed with respect to the Fiber Optic Facilities or Pathnet's
            leasehold interest. Pathnet shall indemnify, defend and hold BNSF
            harmless against the payment of any Taxes referenced in this Section
            24(a).

                  (b) BNSF may pay any Taxes, plus any penalty and/or interest
            thereon, imposed upon BNSF for which Pathnet is obligated pursuant
            to this Lease, if Pathnet



                                       25
<PAGE>   26



            does not pay such Taxes when due, and Pathnet shall promptly
            reimburse BNSF for any such payment it makes.

                  (c) In the case of amounts described in Section 24(a)(ii),
            where Taxes with respect to Fiber Optic Facilities or Pathnet's
            leasehold interest are not separately assessed, BNSF shall determine
            the amount of Taxes attributable to the Fiber Optic Facilities and
            Pathnet's leasehold interest by reference to information provided by
            the relevant taxing authority that demonstrates or establishes that
            such Taxes are attributable to the Fiber Optic Facilities or
            Pathnet's leasehold interest. If the information provided by the
            relevant taxing authority demonstrates or establishes that Taxes are
            attributable to the fiber optic value of a Rail Corridor in respect
            of which Pathnet has been granted rights hereunder, but does not
            demonstrate or establish the value attributable to the Fiber Optic
            Facilities or Pathnet's leasehold interest, the amount so
            attributable shall be determined by reference to a formula. Such
            formula shall be consistently applied, shall reasonably allocate any
            Taxes among all of BNSF's rail corridors and fiber optic values with
            a further allocation of the Taxes attributable to the fiber optic
            value between the Fiber Optic Facilities, Pathnet's leasehold
            interest and fiber optic value attributable to fiber optic rights
            granted by BNSF to others. In all cases, BNSF promptly shall provide
            to Pathnet information that establishes the manner in which any such
            Taxes were allocated and the basis for establishing that such
            amounts are attributable to the Fiber Optic Facilities or Pathnet's
            leasehold interest. The parties shall resolve any dispute regarding
            the liability of Taxes hereunder pursuant to the dispute resolution
            and arbitration procedures set forth in Section 21 of this Lease.

                  (d) Notwithstanding anything to the contrary contained in this
            Lease, BNSF shall pay (i) any Taxes attributable to rights in the
            Fiber Optic Facilities and other assets and services provided to
            BNSF pursuant to Section 8 of this Lease; and (ii) property,
            franchise or similar taxes that are attributable to a Rail Corridor
            that are not attributable to the existence or use of the Fiber Optic
            Facilities or Pathnet's leasehold interest. BNSF shall indemnify,
            defend and hold Pathnet harmless against the payment of any Taxes
            referenced in this Section 24(d). Pathnet may pay any Taxes imposed
            on Pathnet for which BNSF is obligated to indemnify Pathnet pursuant
            to this Section 24(d), if BNSF does not pay such amounts when due
            and BNSF shall promptly reimburse Pathnet for any such payment it
            makes. The provision of Section 24(c) shall apply to amounts claimed
            by Pathnet, mutatis mutandis.

                  (e) Neither BNSF nor Pathnet will be responsible for the
            income or corporate franchise tax of the other.

                  (f) Both BNSF and Pathnet agree to reasonably cooperate with
            each other in the refund, rebate, reduction, abatement, mitigation
            or contest of any Taxes for which either is obligated to pay
            hereunder.

            25.   Independent Contractor Status; No Joint Venture. BNSF reserves
no control whatsoever over the employment, discharge or compensation of
Pathnet's employees or contractors. It is the intention of the parties hereto
that Pathnet shall be and remain an independent contractor, and nothing in this
Lease shall be construed as inconsistent with



                                       26
<PAGE>   27



Pathnet's independent contractor status or creating or implying any partnership
or joint venture between Pathnet and BNSF.

            26.   Confidentiality.

                        (a) The terms of this Lease shall be confidential.
            Either party hereto may designate as confidential certain materials,
            maps, documents and other information exchanged in fulfilling the
            terms and intent of this Lease. In addition, in connection with the
            provision of material and/or services to BNSF by Pathnet, or to
            BNSF, BNSF and/or Pathnet may discover or otherwise come into
            contact with specifications, drawings, computer programs, and/or
            technical or business information which BNSF or Pathnet has clearly
            identified as confidential. All construction plans, drawings and
            specifications, including, without limitation, all proposed
            Construction Drawings, Final Construction drawings and as-built
            plans and all information about the location of the Fiber Optic
            Facilities, will constitute confidential information.

                        (b) Unless confidential information was previously known
            free of any obligation to keep it confidential, or has been or is
            subsequently made public, it shall be handled in confidence by BNSF
            and Pathnet and shall be disclosed only upon a need to know basis,
            such terms and conditions as may be mutually agreed upon in writing
            by the parties hereto, or as required by law. BNSF and Pathnet shall
            advise those employees, agents, and contractors who may have contact
            with such information, of the obligation to keep such information
            confidential, and will use their best efforts to avoid unauthorized
            disclosure of such information. Notwithstanding the foregoing,
            either party may disclose confidential information to the extent
            required by applicable law or regulations, provided that the
            disclosing party has notified the other party of the disclosing
            party's obligation to disclose, and provided that the non-disclosing
            party has had an opportunity to contest such disclosure.

                        (c) In the event of an actual or threatened disclosure
            of such information by either party hereto which might cause
            irreparable harm to the other party hereto, it is agreed that
            monetary remedies available at law may be inadequate and, therefore,
            the aggrieved or threatened party hereto shall be entitled to
            receive injunctive relief as an equitable remedy.

                        (d) Notwithstanding anything else herein, the
            obligations of the parties hereto under this Section 26 shall
            survive termination of this Lease for a period of three years.

            27.   Assignment.

                        (a) This Lease shall be binding upon and inure to the
            benefit of the parties hereto and their respective permitted
            successors or assignees. Pathnet shall not assign any of the rights
            granted to Pathnet under this Lease, without the prior written
            consent of BNSF, which may be withheld or conditioned in BNSF's sole



                                       27
<PAGE>   28

            discretion. Any assignment made in violation of this Section 27
            shall be null and void, shall confer no rights upon any party as
            against BNSF, and shall give BNSF the right to terminate this Lease
            effective immediately, or take any other lesser action with respect
            thereto. The above requirement for consent shall not apply to (i)
            any disposition of all or substantially all of Pathnet's stock or
            assets; (ii) any corporate merger, consolidation or reorganization,
            whether voluntary or involuntary, involving Pathnet; or (iii) a
            sublease or assignment of the Lease (in whole or in part) by Pathnet
            to a subsidiary, affiliate, or parent company, controlled, under
            common control with, or controlling, either indirectly or directly,
            Pathnet, but only where, and to the extent, such transaction does
            not violate the terms of the Contribution Agreement; provided that
            no assignment not consented to by BNSF shall relieve Pathnet of any
            of its obligations or liabilities under this Lease. Nothing herein
            shall prohibit Pathnet (i) from involving contractors, or strategic
            or co-development partners in Construction and Operation of the
            Fiber Optic Facilities, on such terms as Pathnet may determine in
            its sole discretion, provided all such activities are conducted in
            accordance with the terms of this Lease, and that Pathnet remains
            fully liable for all obligations hereunder; and (ii) from granting
            liens or other security interests in the Fiber Optic Facilities or
            Pathnet's rights under this Lease in connection with financing or
            investments made available to Pathnet.

                        (b) Upon request by Pathnet, BNSF shall execute
            reasonable documentation to be provided by Pathnet acknowledging the
            rights of Pathnet's lender(s) ("Lender") to obtain ownership of the
            Fiber Optic Facilities if this Lease is still in effect and Pathnet
            is in material default under the terms of Pathnet's loan to Lender,
            provided, however, that in such case Lender shall become an assignee
            to this Lease and shall become subject to all rights and obligations
            of Pathnet under the terms of this Lease (and Pathnet also shall
            remain subject to all obligations of Pathnet under this Lease). In
            order to obtain the rights specified in this Lease, Lender must
            execute an amendment to this Lease agreeing to be bound by the
            terms, conditions and obligations contained in this Lease. The
            execution of such an amendment by Lender shall not relieve Pathnet
            from any obligations or liabilities contained in this Lease.
            Further, before Lender or any other assignee or transferee of
            Pathnet's interest in this Agreement may obtain any of Pathnet's
            rights hereunder, such Lender, assignee, or transferee must cure any
            and all outstanding defaults by Pathnet hereunder. In addition to
            the rights granted to Pathnet hereunder, Pathnet's Lender shall have
            the additional right to take possession, sell, assign or otherwise
            transfer the Fiber Optic Facilities, including the right to operate,
            or permit a third-party to operate, the Fiber Optic Facilities,
            provided such operation shall be subject to all terms and conditions
            of this Lease.

            28.   Notices. Unless otherwise provided herein, all notices and
other communications required by or concerning this Lease shall be in writing
and shall be deemed to have been duly given when delivered in person or on the
next business day when sent by a nationally recognized overnight courier, or on
the second succeeding business day when sent by registered or certified



                                       28
<PAGE>   29

United States Mail (postage prepaid, return receipt requested), or, if postal
claim notice is given, on the date of its return marked "unclaimed" (provided,
however, that upon receipt of a returned notice marked "unclaimed", the sending
party hereto shall make reasonable effort to contact and notify the other party
hereto by telephone) and each respective party hereto at the following addresses
(or at such other address for a party hereto as shall be specified by like
notice):

            (1)   if to Pathnet:

                  Pathnet, Inc.
                  1015 31st St., N.W.
                  Washington, DC 20007
                  Attn: General Counsel

                  and to:

                  Pathnet, Inc.
                  1661 Gateway Boulevard
                  Richardson, TX 75080
                  Attn:  Senior Vice President, Engineering

            (2)   if to BNSF:

                  Assistant Vice President, Telecommunications
                  The Burlington Northern and Santa Fe Railway Company
                  2600 Lou Menk Drive
                  Forth Worth, Texas 76131

                  and to:

                  Vice President -Law
                  The Burlington Northern and Santa Fe Railway Company
                  2500 Lou Menk Drive, AOB-3
                  Fort Worth, Texas 76131-2830

            29.   Brokers and Agents. BNSF and Pathnet represent and warrant to
each other than neither has employed any broker, agent or finder in connection
with this Lease, and each indemnifies and agrees to hold harmless the other from
and against any commission or fee claimed by any broker, agent or finder in
connection with this transaction.

            30.   Force Majeure. Except as may be elsewhere specifically
provided in this Lease, any failure or delay in the performance by a party
hereto of its obligations hereunder, including, without limitation, Pathnet's
obligations pursuant to Section 5 hereof, shall not be a breach of this Lease if
such failure or delay results from causes beyond that party's control, including
but not limited to acts of God, governmental action or inaction (whether in its
sovereign or contractual capacity), fire, flood, or other catastrophe, national
emergency, insurrection, riot, and




                                       29
<PAGE>   30

war. The phrase "beyond that party's control" shall not include any failure to
reach agreement with a party with whom Pathnet is negotiating pursuant to the
exclusive right to negotiate provided in Section 4(b) of the Fiber Optic Access
Agreement.

            31.   Costs. Except as specifically provided in this Lease, each
party hereto shall be responsible for its own costs (including legal fees)
incurred in connection with the preparation, execution and performance of this
Lease.

            32.   Severability. If any provision of this Lease or the
application thereof, shall be held invalid, illegal or unenforceable in whole or
in part, the remainder of this Lease and the application thereof shall not be
affected, and shall be enforceable to the fullest extent permitted by law, and
the portion hereof found to be invalid shall be enforced to the fullest extend
permitted by law, and, if possible, shall be reformed to carry out as much as
possible the intent of the parties as expressed herein.

            33.   Amendment, Waiver. This Lease may be amended only by a written
instrument executed by both parties hereto. No failure to exercise and no delay
in exercising, on the part of a party hereto, any right, power or privilege
hereunder shall operate as a waiver of any other provision of this Lease, or as
a waiver of that right, power or privilege either before, or after, the period
of waiver.

            34.   Entire Agreement. This Lease and all Exhibits attached hereto,
together with the Fiber Optic Access Agreement and the Contribution Agreement
between the parties hereto dated as of __________ __, 1999, constitute the
entire agreement of the parties hereto with respect to the subject matters
hereof, and supersede any and all prior negotiations, understandings and
agreements, whether oral or written, with respect hereto.

            35.   Interpretation; Construction.

                  (a) Section headings contained in this Lease are solely for
            purpose of reference and shall not be construed with the substance
            of the Section they caption or in any way affect the meaning or
            interpretation of this Lease.

                  (b) Wherever used in this Lease: (i) any pronoun or pronouns
            shall be deemed to include both the plural and the singular and to
            cover all genders, and (ii) "or" is used in the inclusive sense, in
            all cases where such meanings would be appropriate.

            36.   Legal Forum. This Lease shall be interpreted, construed and
enforced in accordance with the laws of the State of Texas.

            37.   Counterparts. This Lease may be executed in one or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute but one and the same instrument.


                                       30
<PAGE>   31



IN WITNESS WHEREOF, authorized representatives of BNSF and Pathnet have executed
this Lease as of the date first set forth herein.


PATHNET TELECOMMUNICATIONS, INC.             THE BURLINGTON NORTHERN AND
                                             SANTA FE RAILWAY COMPANY

By:                                          By:
        -----------------------------               ---------------------------
Name:                                        Name:
        -----------------------------               ---------------------------
Title:                                       Title:
        -----------------------------               ---------------------------




                                       31
<PAGE>   32
                                  EXHIBIT A





                        [to be agreed to by the parties]


<PAGE>   33
                                  EXHIBIT B




                          Map of BNSF Railway Network

                        [to be agreed to by the parties]


<PAGE>   34
                                   EXHIBIT C

                     Additional Construction Specifications
                     --------------------------------------

                        [to be agreed to by the parties]