<PAGE>
                                                                Exhibit 10.12.4

                            FIFTH AMENDMENT TO LEASE

THIS AMENDMENT, made and entered into this 29th day of June, 2004, by and
between PARK SPE, LLC, hereinafter called "Lessor," and CXT INCORPORATED, a
Delaware corporation hereinafter called "Lessee."

                                    RECITALS

WHEREAS, on April 1, 1993, the Lessor and Lessee entered into an agreement of
Lease covering those certain premises described as a portion of those certain
premises described as Spokane County Altered Binding Site Plan No. 87-17,
Spokane County Binding Site Plan No. 88-21, and Spokane County Binding Site Plan
No. 88-22, containing approximately 8,619,217 gross square feet (Building S-16),
located at 3808 North Sullivan Road, situated in the County of Spokane, the
State of Washington.

WHEREAS, on March 28, 1996 the Lessor and Lessee entered into a First Amendment
to Lease covering those certain premises whereby expanding its Premises to
include 2.765 acres of Parcel A (located East of Tract A) and increasing the
monthly Base Rent and Common Area Expenses.

WHEREAS, on June 30, 1999 the Lessor and Lessee entered into an Amendment to
Lease covering those certain premises whereby Lessee entered into a transaction
wherein its stockholders sold all of their stock to L.B. Foster Company, which
sales constituted a transfer of the Lessee's interest in the Lease requiring
Lessor's consent. The Lease and all addendums and amendments thereto are
hereinafter collectively referred to as the "Lease."

WHEREAS, on November 7, 2002 the Lessor and Lessee entered into a Third
Amendment to Lease covering those certain premises whereby extending the Term of
the Lease for an additional year effective January 1, 2003.

WHEREAS, on December 15, 2003 the Lessor and Lessee entered into a Fourth
Amendment to Lease covering those certain premises whereby extending the Term of
the Lease for an additional seven (7) months effective January 1, 2004.

WHEREAS, the said Lessee now desires to extend the term of the Lease for an
additional two (2) year period effective August 1, 2004.

NOW, THEREFORE, in consideration of the Premises and agreements herein
contained, it is hereby agreed as follows:

Article 3. Term, shall be amended as follows:

     The Term of the Lease shall be extended for an additional two (2) year
period effective August 1, 2004 and shall end on July 31, 2006. Additionally,
Lessor and Lessee agree to execute this Fifth Amendment to Lease rather than the
execution of a new lease as stipulated in Article 3 of the Fourth Amendment to
Lease.

Article 4. Base Rent, paragraph 4.1, shall be amended as follows:

<TABLE>
<S>                                         <C>
     August 1, 2004 through July 31, 2006   $18,541.00 per month
</TABLE>

     EXCEPT for the new terms and conditions listed above, all other terms and
conditions of the Lease and any subsequent amendment(s) shall remain in full
force and effect.
<PAGE>
     IN WITNESS WHEREOF, the said Lessor and Lessee have executed this amendment
to lease the day and year first written above.

LESSOR:                                    LESSEE:

PARK SPE, LLC                              CXT INCORPORATED
                                           A Delaware corporation


/s/ Rob B. Gragg                           /s/ Dave Millard
---------------------------------------    -------------------------------------
Rob B. Gragg, Authorized Representative    Dave Millard, Vice President
<PAGE>
STATE OF WASHINGTON )
                    ) ss.
COUNTY OF SPOKANE   )

On this 23rd day of July, 2004, personally appeared Rob B. Gragg to me known to
be the Authorized Representative of PARK SPE, LLC, the limited liability
company, that executed the within and foregoing instrument, and acknowledged the
said instrument to be the free and voluntary act and deed of said company, for
the uses and purposes therein mentioned, and on oath stated that he was
authorized to execute the said instrument.

IN WITNESS WHEREOF, I have hereunto set my hand and affixed my official seal the
day and year first above written.


                                           /s/ Marci Combs
                                           -------------------------------------
                                           Name Printed: Marci Combs
                                           NOTARY PUBLIC in and for the State
                                           of Washington, residing at Spokane
                                           Valley.

                                           My Commission Expires: 8-1-06

STATE OF WASHINGTON )
                    ) ss.
COUNTY OF SPOKANE   )

On this 16th day of July, 2004, personally appeared Dave Millard to me known to
be the Vice President of CXT INCORPORATED, the Delaware corporation, that
executed the within and foregoing instrument, and acknowledged the said
instrument to be the free and voluntary act and deed of said company, for the
uses and purposes therein mentioned, and on oath stated that he was authorized
to execute the said instrument.

IN WITNESS WHEREOF, I have hereunto set my hand and affixed my official seal the
day and year first above written.


                                           /s/ Tina M. Bucklin
                                           -------------------------------------
                                           Name Printed: Tina M. Bucklin
                                           NOTARY PUBLIC in and for the State
                                           of Washington, residing at 12411
                                           E. Mansfield Ave. #7 Spokane Valley,
                                           WA 99216

                                           My Commission Expires: June 20, 2008