E PLURIBUS UNUM

NATIONAL TRA SPORTATION

B OARD

SAFE T Y

N

National Transportation Safety Board 

Washington, D.C. 20594

Railroad Accident Brief

Accident Number: DCA-01-MR-004

Location: Baltimore, Maryland 

Date and Time: July 18, 2001, 3:08 p.m. 

Accident Type: Derailment and fire 

Companies: CSX Transportation 

Injuries: 5 (minor) 

Fatalities: None 

Cost: $12 million 

Synopsis 

On Wednesday, July 18, 2001, at 3:08 p.m., eastbound CSX1 freight train L-412-

16 derailed 11 of its 60 cars while passing through the Howard Street Tunnel in 

Baltimore, Maryland. Four of the 11 derailed cars were tank cars: 1 contained 

tripropylene, a flammable liquid; 2 contained hydrochloric acid; and 1 contained di(2-

ethylhexyl) phthalate, which is a plasticizer and an environmentally hazardous substance. 

The derailed tank car containing tripropylene was punctured, and the escaping 

tripropylene ignited. The fire spread to the contents of several adjacent cars, creating 

heat, smoke, and fumes that restricted access to the tunnel for several days. A 40-inchdiameter water main directly above the tunnel broke in the hours following the accident 

and flooded the tunnel with millions of gallons of water. Five emergency responders 

sustained minor injuries while involved with the on-site emergency. Total costs

associated with the accident, including response and clean-up costs, were estimated at 

about $12 million. 

The Accident 

The train, en route with 31 loaded and 29 empty cars from West Baltimore, 

Maryland, to Philadelphia, Pennsylvania, departed the CSX West Baltimore Yard, about 

6 miles west of the derailment site, at 2:37 p.m. on July 18, 2001. Within its consist, the 

train had eight fully loaded tank cars containing hazardous materials regulated by the 

U.S. Department of Transportation (DOT). 

On the day of the accident, 11 trains went through the Howard Street Tunnel 

before the accident train. The crewmembers of the accident train reported that their train

 1

 CSX is more formally known as CSX Transportation or CSXT, a subsidiary of CSX Corporation.

 1 NTSB/RAB-04/08
entered the west end of the tunnel (Camden end)2

 at a speed of 23 mph. The locomotive 

event recorders indicated that the locomotives were in throttle position 5 and that the 

train’s speed was less than the timetable speed of 25 mph as the train entered the tunnel. 

About 1,343 feet into the 8,700-foot-long tunnel (station 73+57),3

 the track grade

changes from a slight descending grade to a slight ascending grade. The event recorders 

showed that at the dip, the train’s speed was 24 mph in throttle position 4. As the train 

passed through the dip, the engineer gradually increased the throttle to position 8 as the

train started the ascending grade. While the train was moving about 21 mph, the 

locomotive tractive effort increased, and the train slowed to 18 mph. At 3:08 p.m., an 

uncommanded emergency air brake application4

 was recorded, and the lead locomotive 

stopped in the tunnel about 1,850 feet from the east portal. 

Unknown to the crew at the time, the train had derailed. The emergency 

application of the train air brakes had occurred when the train became uncoupled ahead

of the first car to derail, causing the train air brake line to separate. 

The derailment also resulted in the puncturing of a derailed tank car carrying 

tripropylene and the subsequent ignition of this product. The puncture was a 2-inchdiameter hole located near the bottom of the tank on the B-end (the leading end), left 

side, and on line with the interior end of the stub sill. Postaccident inspection of the tank 

car indicated that a braking system linkage bar had disconnected and that the 

disconnected end of the linkage bar, when lifted upward, aligned with the hole in the 

tank. The fire spread to cargo in adjacent cars, which included paper and wood products, 

and generated heavy smoke and fumes that quickly filled the tunnel. Additionally, 2,554 

gallons of hydrochloric acid were released from another derailed tank car. (See figure 1 

for a diagram showing the positions of the derailed cars.) 

 2

 For identification purposes, the timetable tunnel orientations are used. The geographic south end

(Camden) of the tunnel is designated as the west end in the timetable, and the geographic north end (Mt.

Royal) is designated as the east end. 

3

 CSX uses station numbers to identify specific locations within the Howard Street Tunnel. Each

station represents a distance of 100 feet measured from the east end (Mt. Royal portal) of the tunnel. 

Locations in the tunnel are identified by indicating the number of feet they are west of the nearest station

marker. For example, station 73+57 is about 7,357 feet from the east portal of the tunnel. 

4

 Railroads typically refer to any emergency brake application not specifically initiated by the engineer 

as an “undesired” emergency brake application. 

 2 NTSB/RAB-04/08
Figure 1. Positions of derailed cars. 

The lead locomotive stopped inside the tunnel about 1,850 feet west of the Mt. 

Royal portal. For some time, the train crewmembers remained unaware that a derailment

had taken place. When the crewmembers attempted to notify the CSX dispatcher while 

their locomotive was still in the tunnel, they found they could not establish radio contact.5

About 3:13 p.m., the conductor used his personal cell phone to contact a Baltimore area 

trainmaster, who relayed information regarding the emergency stop to the train

dispatcher. About 3:26 p.m., the crew moved the locomotives eastward out of the tunnel, 

stopping about 450 feet beyond the east tunnel portal. 

Postaccident Events and Emergency Response 

At 3:26 p.m., the director of security at a hotel above and adjacent to the 

derailment site in the tunnel called 911 and reported an unusual disturbance near his 

facility. The security director then called the Baltimore Department of Public Works to 

report the disturbance. About 3:34 p.m., he called the CSX communications center to 

advise them of a strong “rumbling” that had occurred at his building. He told the 

communications center that he suspected the rumbling had originated in the Howard

Street railroad tunnel. About 3:36 p.m., the communications center operator forwarded 

the call directly to the CSX chief dispatcher. 

 5

 It was later learned that derailing equipment had rendered the radio relay system inoperable. 

 3 NTSB/RAB-04/08
The CSX chief dispatcher contacted the Baltimore trainmaster to advise him of 

the situation and ask if the train was transporting hazardous materials. He was told that 

the train did include hazardous materials cars. About 3:40 p.m., the CSX chief dispatcher 

determined that the train likely had a serious problem and had possibly derailed. 

At 3:51 p.m., the CSX director of network operations issued a request for 

assistance to the railroad’s hazardous materials team. About 4:00 p.m., Baltimore 911 

received a call reporting smoke coming from a sewer near the Howard and Lombard 

Street intersection. Fire department responders were dispatched, and they traced the 

smoke to the Camden (west) tunnel portal. 

Also about 4:00 p.m., the CSX chief dispatcher telephoned the CSX police 

communications center to ask that the Baltimore City Fire Department be notified and

that emergency response personnel be dispatched to the tunnel. At 4:04 p.m., the CSX 

police communications center notified the Baltimore 911 operator, who notified the

Baltimore City Fire Department. Fire department personnel responded to the site (Mt. 

Royal Station) about 4:10 p.m., but they could not enter the tunnel because of the fire and 

smoke. The train crew provided the train consist6

 to the emergency responders. 

About 5:07 p.m., the incident commander, after deliberating with the responding 

technical experts, concluded that the derailment did not pose an immediate threat of a 

catastrophic explosion or a dangerous vapor release that would require an evacuation of 

the area. The incident commander thus did not believe a mass evacuation was necessary

and instead decided to employ a “shelter-in-place” strategy for the several blocks on 

either side of the tunnel path along the principal length of the tunnel. Other precautionary 

measures included evacuating the Camden Yards baseball stadium, activating the public 

alert siren system, and employing local television and radio outlets for public 

notifications. 

About 6:15 p.m., the water elevation began dropping at the city of Baltimore’s 

Montebello II treatment plant. About 6:19 p.m., the water elevation at the Montebello I

water treatment plant also began dropping. At Druid Park Lake, the water flow rate7

abruptly increased from about 8.5 million to 9 million gallons per day (mgd) to about 18 

mgd between about 6:15 p.m. and 6:30 p.m.

A time-stamped security camera (taking a picture every 48 seconds) showed that 

water had broken through to the street surface at the intersection of Howard and Lombard 

Streets at 6:19:38 p.m. Water flooded the intersection and flowed south on Howard 

Street. Water also flowed into the Howard Street Tunnel, which was below the street. 

 6

 The train consist shows the make-up of the train, including the placement and contents of all cars. If

cars containing hazardous materials are part of the train, documentation is attached to the consist list that

details emergency response information for those materials. 

7 Flow rate is a measurement of the volume of water leaving the reservoir and entering into the water 

system over a given period of time. 

 4 NTSB/RAB-04/08
According to city records, notification was received of a water leak about 

6:19 p.m., and the city sent a crew to investigate. The crew determined that a failure had 

occurred in the 40-inch-diameter cast iron water main that passes directly above the 

Howard Street Tunnel at station 63+15.8

 (See figure 2 showing broken water main.) The 

crew closed a 40-inch valve at the intersection of Lombard and Paca Streets. They also

closed valves on an interconnected 20-inch-diameter water line. A 40-inch valve located 

1 block to the east (as well as numerous interconnecting lines) was also closed to isolate 

the area of the break. The line was shut down by 11:59 p.m., about 5 hours 40 minutes 

after the appearance of water at street level. The city of Baltimore estimated that about 14 

million gallons of water were lost from the water main between the time of the break and 

the time the line was shut down. 

Figure 2. Broken 40-inch-diameter water main. 

For the next 2 days, several groups of firefighters and railroad employees

equipped with self-contained breathing apparatus ventured into the tunnel to determine 

the extent of the derailment and the status of burning equipment and cargo. Inside the 

tunnel, the first 45 railcars in the train consist had not derailed and had been pulled 

 8

 The city calculated the water pressure of the 40-inch pipe at the point of the tunnel crossing to be

about 73 pounds per square inch. 

 5 NTSB/RAB-04/08
beyond the derailment site. The next 11 railcars had derailed (positions 46 through 56). 

The remaining four railcars had not derailed. 

The fire lasted for about 5 days as smoke emanated from both ends of the tunnel 

and several manholes at the Howard Street level. On Monday, July 23, at 7:42 a.m., the 

incident commander declared the scene officially under control. Later that morning, he 

authorized entry into the tunnel without self-contained breathing apparatus for qualified 

personnel. 

Efforts to Determine Accident Cause 

General 

Because of the fire in the tunnel and the release of hazardous materials from tank

cars, Safety Board investigators were not immediately able to enter the tunnel. By the 

time Safety Board investigators were able to examine the derailment area in detail, it had

been disturbed by the discharge of about 14 million gallons of water from the ruptured

water main, by the removal of significant sections of track, and by the use of heavy 

equipment to pull smoldering cars from the tunnel. Investigators therefore could not 

document the derailment site as would normally be done in a train derailment accident 

investigation. The following material considers preaccident data and information, 

postaccident physical testing and evidence, and statements from people who were in the 

tunnel during or immediately after the emergency response. 

Postaccident examination did not disclose any preaccident defective rail 

conditions. All the fractures in the north rail initiated from the gage side, and almost all 

the fractures in this rail were associated with a rail anchor mark. This indicates that the 

fractures in the north rail were created by a common mechanism. The most likely 

mechanism was a wheel or wheels dropping off the gage side of the north rail and 

striking the anchors, driving them in an eastward direction. The anchor marks were likely 

created when a struck anchor, restrained by a tie, dug into the gage side of the base, 

creating a depression and, in many cases, initiating a shear crack at the east end of the 

mark. These shear cracks then propagated and fractured the north rail. 

None of the fractures found after the accident contained any features that 

suggested a defect or a slow-growing crack. Additionally, the investigation did not find

any battered rail ends, as would be expected if a rail had broken before the accident. All 

the fractures found in the rail removed from the accident area were typical of overstress 

fracture, indicating that a broken or defective rail did not cause the derailment.

Examination of the event recorder data for the accident train did not show any 

unusual train handling methods, and the engineer and conductor performed their assigned 

tasks in compliance with the CSX operating rules and special instructions applicable to 

this train’s operation. A review of the crewmen’s personnel records showed they were 

 6 NTSB/RAB-04/08
current in the operating rules requirements for their positions, and their medical records 

did not show restrictions.

Inspections of the train equipment did not reveal any preaccident deficiencies,

defects, or missing parts, with the exception of the 52nd car in the consist. The 52nd car, 

the derailed tripropylene tank car that ruptured, was found de-trucked, with its 

easternmost (lead) truck near the center of the car and the westernmost truck against the

car body bolster. The center pin between the lead truck and car body was missing.9

 The 

Safety Board and the Association of American Railroads (AAR) used computer models 

to simulate the movement of this car with the center pin missing between the lead truck 

and car body. The simulation used the most recent CSX track geometry data for the 

segment of track with the train entering the west portal of the tunnel at the speed of 23 

mph. The simulation did not result in a derailment of the tank car with a missing center 

pin. 

The 40-inch-diameter cast iron water main that ran directly above the Howard 

Street Tunnel, which ruptured and introduced a large volume of water into the tunnel, 

was considered as a possible causal factor in the accident. When postaccident 

examination was made of the ruptured pipe, no indication of third-party damage or 

significant corrosion damage was found at or near the point of rupture. Metallurgical 

examination of the fractured pieces of the water main showed that the fractures in the

pipe section were brittle, with no evidence of crack arrest positions or slow growth

regions, which indicates that a sudden overstress fracture of the cast iron pipe occurred. 

A photo from a time-stamped security camera at the intersection of Howard and 

Lombard Streets indicated that water from the broken main appeared at the street surface 

at 6:19:38 p.m., about 3 1/4 hours after the derailment. In addition, water elevations at 

several nearby water treatment plants declined between about 6:15 p.m. and 6:30 p.m. 

This timing information suggests that the water main broke as a result of the postaccident 

events, including the fire within the tunnel, rather than prior to the accident. 

A finite element analysis10 of the tunnel and surrounding area in the vicinity of the 

water main was performed using the ABAQUS11 code to determine whether the fire

within the tunnel could have caused the water main to fracture. The analysis concluded 

that the postaccident fire was responsible for thermal expansion of the tunnel and that the 

expansion caused the tunnel walls to heave upwards, displacing the surrounding materials 

and imparting significant loads upon the water pipe. Further, the unique construction 

 9

 A center pin does not carry or transmit load during a car’s movement. 

10 Finite element analysis is the simulation of a physical system (geometry and loading environment)

by a mathematical approximation of the real system. Using interrelated building blocks called elements, a 

real system with infinite unknowns is approximated with a finite number of unknowns. 

11 Hibbitt, Karlsson & Sorensen, Inc., ABAQUS/Standard User’s Manual, Version 6.2 (Pawtucket, RI: 

2001). 

 7 NTSB/RAB-04/08
details of the tunnel, the pipe, and the light rail foundation12

 combined to generate 

discontinuities in resistance to the thermal heaving, generating significant concentrations 

of stress within the water pipe. The location of the high stress concentrations predicted by 

the analysis was consistent with the location of the initiation of the fracture in the pipe, as

determined through metallurgical examination. Therefore, the 40-inch water main that 

ran directly above the Howard Street Tunnel broke after the train had derailed, as a result 

of the thermal expansion of the tunnel caused by the postaccident fire within the tunnel. 

Identifying the Point of Derailment 

Wheel marks found on the head of the north rail during the reconstruction of rail 

recovered from the derailment area indicated that a wheel had moved south toward the 

inside of the rail about station 62+23. Additional wheel marks were found on the gage 

side of the base of the north rail; however, no wheel marks were found on the south rail 

nor were any other wheel marks identified on either rail. 

A detailed postaccident examination was conducted of the first several derailed 

cars. Efforts were concentrated on the first several derailed cars because experience has 

shown that a derailed car does not cause the derailment of more than two preceding cars

on straight track. The inspection of the truck side frame spring seat ribs of the derailed 

cars showed that the profile of the rail head was worn into the spring seat ribs on the

underside of the truck side frame spring seats on one side or the other of the 46th through 

48th cars, indicating that they had slid on top of the rail between the body of the side 

frame and the wheels. The wear varied from car to car; the more wear there was, the 

longer the car had been derailed before coming to a stop. 

The 47th car in the consist showed the most rib wear, indicating that this car had 

spent the most time derailed, so it was probably the first car to derail. The trucks of the

46th car had the next most rib wear. There was less wear to the B-end (leading end) 

spring seat ribs of the 48th car and only scrapes to the A-end (trailing end) ribs. 

Therefore, it appears that the 46th car was the second car to derail (pulled off the track by 

the 47th car) and that its derailment was followed by the derailment of the 48th and 

subsequent cars. 

Event recorder data showed an increase in the train’s tractive effort, followed by 

an unexpected reduction in train line air brake pressure. Based on this information, the 

Safety Board determined that derailed cars were on the ground while the train traveled 

about 300 feet before an air brake line separation between the 45th and 46th cars caused 

an automatic emergency application of the train’s brakes. From the event recorder data 

and the documented position of the derailed equipment, the 45th and 46th cars came to a 

stop with about 550 to 600 feet between them. Event recorder data showed that the head 

 12 The Maryland Transit Administration operates a double-track light rail service on Howard Street that 

runs parallel to and above the Howard Street Tunnel. 

 8 NTSB/RAB-04/08
end of the 47th car was at about station 62+11, about 12 feet past the wheel marks on the 

north rail, when the emergency application occurred. 

Based on the rail reconstruction, the profile of the rail head wear found on the 

truck side frame spring seat ribs of the car showing the most wear, and the position of the

47th car before the train brakes automatically went into emergency, the point of 

derailment was near station 62+23. 

Derailment Scenarios 

Because no clear evidence was found that would point definitively toward a single 

cause of the derailment, the Safety Board examined several scenarios to determine what

factors or combinations of factors may have caused or contributed to this accident. 

Sand in the Tunnel. Sand was reported in the derailment area after the accident.

Large quantities of sand, if deposited on the track and over the rail, could affect train

passage. But none of the 11 train crews that traversed the tunnel before the accident train 

on the day of the derailment reported seeing unusual quantities of sand on or near the 

track in the tunnel. Nor did the crew of the accident train report observing any unusual 

sand deposits. A quantity of sand sufficient to cause a derailment would not likely have

gone unnoticed. Furthermore, had such an amount of sand been present, the derailment

should have occurred nearer the head end of the train than the 47th car. 

Some of the witnesses who entered the tunnel on the day after the accident

reported seeing little sand in the derailment area. Other witnesses reported seeing 

significant amounts of sand. A fire department chief reported that he inspected the 

undercarriages of the derailed cars and did not notice any sand. 

During postaccident examination, a section of the south wall of the tunnel was 

found to have a bulge projecting into the tunnel near station 62+31. The bulge was about 

8 feet above the tunnel floor and about 4 to 6 feet in diameter. It projected into the tunnel 

less than 1 foot. Within the bulged area was a hole. The hole in the first layer of brick 

was about 3 bricks wide by 3 bricks high. Deeper in the wall, the hole was about 2 bricks 

wide and 1 1/2 bricks high. A person working in the tunnel the day after the derailment 

reported seeing water shooting from this hole, as it was from other locations. 

The Safety Board contracted with the U.S. Army Corps of Engineers (USACE) to 

perform a geotechnical investigation in the area of the tunnel fire and water main break. 

In its report to the Safety Board, the USACE concluded that any significant quantity of 

sand in the tunnel was almost certainly carried into the tunnel as a result of the piping 

action from the ruptured 40-inch water main. Further, the USACE reported that, even if 

the hole had opened in the south tunnel wall bulge near station 62+31 after the head end

of the train had passed, insufficient sand could have been deposited on the track to cause 

a derailment in the 2 minutes 15 seconds that elapsed from the time the locomotives 

 9 NTSB/RAB-04/08
passed until the first car derailed. The sand on the tunnel floor reported by some 

observers days after the derailment most likely resulted from the postaccident rupture of 

the 40-inch water main above the tunnel and the release of 14 million gallons of water. 

Wide-gage Track. Wide-gage track can lead to a derailment if the defect is 

sufficient to allow the train wheels to drop inside the rails. In this accident, wheel 

markings found after the accident on the north rail could indicate a wide-gage derailment; 

that is, the markings show that derailed wheels did drop into the gage side of the north 

track. Other evidence, however, was not consistent with a wide-gage derailment. 

Typically, in wide-gage derailments, either the wheels on both sides of the solid

axle fall within the gage of the track or the wheels on one side drop in while the opposing 

wheels remain on the rail. In other cases, a wheel drops in and the opposite wheel forces 

the other rail to “roll-over” with that wheel then riding along the web of the rolled rail. 

Physical evidence did not support any of the wide-gage derailment scenarios. The 

south wheels of the derailed cars neither fell within the gage of the track nor remained on

the rail; they were found derailed to the field side (outside) of the track. Also, the 

evidence of the profile of the rail head worn into the spring seat ribs on the underside of 

the truck side frame spring seats on one side or the other of the 46th through 48th cars 

indicates that neither the north nor south rails immediately rolled during the derailment. 

Postaccident track inspection did not identify any crosstie deficiencies within the 

undisturbed track leading to the derailment area. Inspection of the undisturbed track 

crosstie population immediately after the accident and again after completion of a rail 

renewal project did not show any signs of gage widening for the straight track outside or 

within the limits of the derailment footprint. No evidence was found to suggest that the 

condition of the ties that had been destroyed in the fire was significantly different from

the condition of the other crossties in the area. The condition of the recovered crossties 

was also consistent with that of the non-defective resident crosstie population, taking into 

consideration the damage the recovered crossties received from the derailed equipment. 

The fasteners and tie plates on the recovered crossties appeared to be affixed solidly on 

almost every crosstie, indicating that the crossties were likely of sufficient strength not 

only to sustain the postaccident damage but also to maintain gage within the standards for

Federal Railroad Administration (FRA) class 2 track. 

Records showed that CSX tested and/or measured the track geometry through the 

Howard Street Tunnel an average of three times per year. The Safety Board reviewed the

seven previous track geometry tests, which took place over a time span of about 2

years.13 The seven track geometry tests between July 13, 1999, and February 2, 2001, 

showed that the rate of change in gage during the 2-year period was negligible; during 

this time, the gage never reached problematic proportions in the area of the straight track, 

 13 The specific test dates were February 2, 2001; January 30, 2001; July 17, 2000; July 12, 2000; 

March 20, 2000; March 15, 2000; and July 13, 1999. 

 10 NTSB/RAB-04/08
including the area of the derailment. In addition, preaccident track inspections by both 

CSX and the State of Maryland did not identify any gage deficiencies within the tunnel. 

Track Geometry. A train/track dynamic simulation study was undertaken to 

examine the interactions of the track, train, and environment within the Howard Street

Tunnel. When computer simulations were performed using the most recent preaccident 

CSX track geometry data (taken on February 2, 2001) and incorporating the condition of 

the equipment and the dynamic forces applied by the accident train to the track structure,

no simulated derailment occurred. But because an actual derailment did occur, and 

because a broken rail, the mechanical condition of the train, and train operations had not 

been identified as likely factors in the accident, investigators had to consider whether the 

derailment could have been caused by one or more deficiencies in the track structure. 

The CSX track geometry data for the seven most recent previous tests showed 

that the gage, cross-level, alignment, profile, and warp measurements were within FRA 

regulatory thresholds for class 2 track. In fact, the track structure in the straight portion of 

track in and around the point of derailment consistently met standards for FRA class 5 

track (a maximum speed of 80 mph allowable for freight trains),14 even though CSX 

elected to operate its trains at 25 mph through the tunnel. Thus, it is unlikely that a train 

traveling at less than 25 mph, as was the accident train, would have derailed solely due to 

track geometry as measured before the accident. The track geometry test data reviewed 

were representative of an approximately 2-year-long period before the derailment. The

data show that the track alignment fluctuated within a range of about 0 to 1 1/8 inch 

during the entire 2-year period. Further, the track in the tunnel underwent maintenance 

for spot surfacing with crosstie renewal installation. The surfacing of track is consistent 

with normal crosstie installation, and it is likely that the surfacing helped to maintain or 

improve the track alignment for the straight stretch of track in the tunnel. 

Rail cross-level measurements for the same 2-year period also showed improved 

measurements, from a 0- to 1-inch range on July 13, 1999, to a 0- to 3/4-inch range for 

the same portion of straight track on July 17, 2000, almost exactly 1 year before the 

derailment. The range of the cross-level measurements (0 to 3/4 inch) remained constant

for the year preceding the derailment. These measurements do not represent only the 

actual derailment area but rather the overall area of straight track, beginning east of the 

curves at station 71+00 and extending eastward on the straight track, through and past the 

point of derailment. 

None of the track warp measurements had exceeded 1 1/8 inch in the previous 2 

years. Track warp fluctuated from one test with a range of 0 to 1 1/8 inch in July 1999 to

an improved range (a lessening of measurement) of 0 to 1/2 inch for two consecutive test 

 14 It should be noted that although this specific portion of track could have been designated as class 5,

due to practical engineering considerations concerning physical aspects of the Howard Street Tunnel, trains 

could not have been safely operated at speeds of 80 mph within the tunnel because of physical 

characteristics and operational considerations. 

 11 NTSB/RAB-04/08
dates; then track warp increased to a range of 0 to 3/4 inch and remained constant during 

the last three tests prior to the derailment. In each case, the track geometry data 

consistently showed that the higher number in the range of measurements was the 

exception rather than the rule. 

Computer simulations were performed to determine what changes in track

geometry would be required to effect a derailment. The simulations were intended to recreate the accident train’s movement over the track and, by varying the range of track 

geometry conditions, to produce a derailment. 

Simulations were performed in which only one track geometry anomaly was 

introduced, without varying the other track geometry parameters. None of these 

simulations, when based on realistic anomaly data, resulted in a derailment. 

Simulations were also performed using various combinations of anomalies in 

track cross-level, alignment, profile, and warp. These simulations showed that the 

minimum values necessary to create a wheel lift derailment were 2 1/2 inches of crosslevel deviation and 2 1/2 inches of misalignment. But to match these values on the day of 

the accident, the geometry of the accident track would have to have deteriorated at least 

1 3/4 inch vertically and horizontally from the maximum values registered during the 

most recent track geometry car readings, which had been taken about 5 months before the

accident. 

The accident train crew and the crew of the train that had traversed the tunnel 

before the accident train both reported water dripping onto their locomotives and water 

seepage down the tunnel wall near the derailment area, but neither train crew took 

exception to the track conditions within the tunnel. The fact that the 46th and 47th cars of

the accident train were among the first to derail shows that much of the train had 

successfully traversed the area of the derailment. Thus, any combination of track 

anomalies would have had to occur under the passage of the accident train. But the 

essentially consistent track geometry data recorded during the previous 2 years of testing 

did not support the likelihood of extreme or rapid track geometry degradation. 

The investigation showed that the tunnel had chronic water intrusion, particularly 

at the east, or Mt. Royal, end. The intrusion of water would be an outside factor affecting 

the track geometry. CSX was aware of the problem at the Mt. Royal end of the tunnel and 

performed periodic track maintenance to address it. Water from leaks in water 

distribution lines, from storm drains, and from naturally occurring groundwater can seep 

into the tunnel via the various pipeline and electrical conduit paths and accumulate in the 

voids behind the tunnel walls. However, according to the USACE, the Baltimore area had

been suffering from an extended drought at the time of the derailment, and the levels of 

groundwater were probably lower than normal. There had been rainfall of about 1/4 inch 

in the early morning of July 18 in downtown Baltimore. The USACE’s report stated that 

this rainfall would not have contributed a significant amount to either the groundwater or 

the storm water budget in the area. 

 12 NTSB/RAB-04/08
Track Structure Defects and Foreign Object. In the previously described 

scenario, a derailment would have required the track at the point of derailment to have

deteriorated at least 1 3/4 inch vertically and horizontally from the maximum values

registered during the most recent track geometry car inspection. Because such a rapid

deterioration would be inconsistent with the inspection history, investigators considered 

whether a foreign object, when combined with smaller track misalignments, could have 

induced a derailment. 

When a single foreign object was introduced onto the track structure during a 

computer simulation using the most recent track geometry test data, the wheel climbed 

the obstruction, but the car returned to the rail without derailing. Simulation data showed

that to derail a car, an obstruction on the track would have to be combined with 

deterioration in the track geometry sufficient to produce a “steering function.” The 

simulated obstruction lengths varied from 6 to 12 inches. 

The simulations showed that the combination of a 6-inch obstruction on the inside 

of the north rail with a 1 1/2-inch cross-level (vertical) deviation of the south rail and 

1 1/2-inch alignment (lateral) displacement of the track would derail the lead truck of the

car to the south. To obtain the 1 1/2-inch vertical and lateral displacement values, the 

track geometry would have had to deteriorate only 3/4 inch vertically and horizontally 

from the maximum values recorded before the accident. 

A significant factor in this scenario is that the obstruction accounts for the 

“suddenness” of the accident. The simulated obstruction lifted the north wheel, and

because of the steering mechanism of the 1 1/2-inch vertical and lateral track geometry,

the north wheel derailed to the south (the gage side) of the north rail; the solid axle 

construction also caused the south wheel to lift, and the steering mechanism caused it to

pass over the head of the south rail and derail to the south (the field side) of the south rail. 

This is consistent with the wheel markings on the north rail indicating a departure from 

the rails and physical evidence indicating that the 47th car (likely the first car to derail) 

derailed to the south side. However, wheel markings would also be expected on the south 

rail after the wheels passed the obstruction, but none were identified during the 

examination of the recovered rail. 

Investigators considered possible sources of a foreign object or material that could

have caused an obstruction. For example, the postaccident tunnel inspection noted a 2- by 

4-foot void about 5 inches deep in the tunnel ceiling at station 63+15,15 where the 40-inch

water line passes directly above the ceiling with a special saddle section. A CSX 

consultant stated that he believed a previous repair had been made using two layers of 

wire mesh and a mix of brick and a concrete-like substance and that the repair materials

were likely already gone when the fire was burning, because smoke damage was found 

on the surface underneath the repair. No pieces of a repaired section could be linked to 

 15 About 70 to 80 bricks (one brick without mortar measures about 2 1/4 inches by 3 1/2 inches by

7 1/2 inches) could have been contained in the void. 

 13 NTSB/RAB-04/08
the void during the investigation. Smoke damage within the void can be explained by the 

fire and smoke that were in the tunnel for several days following the accident. 

Previously damaged or deteriorated car parts have been known to fall to the track 

and cause derailments when a moving train strikes them. No car parts were missing when 

a postaccident inspection of the first 45 cars of the train was conducted. Additionally, the 

accident train crew did not report seeing debris on the track. 

No convincing evidence was found of a foreign material from the tunnel, a 

previous train, or other source having been present on the track as the accident train 

passed. Further, there is no evidence that the train could have derailed solely based on 

degraded track geometry. Computer simulations indicate that a foreign material between

a wheel and the rail, in combination with certain track geometry degradations, could have 

caused a derailment. 

Tunnel Maintenance and Inspections 

No CSX records were found that described or defined the extent or nature of the 

repairs and modifications that had been made to the tunnel over the years. One CSX 

official told investigators that no records were kept of general maintenance for the 

Howard Street Tunnel. At least some repairs in the tunnel apparently went unrecorded. 

For example, there was the previously cited void in the tunnel’s arch at station 63+15, 

immediately below the 40-inch water main. At some time before the accident, the void 

appears to have been filled with bricks or repair materials, such as concrete patches. 

However, no records of such repairs could be found. 

Water in the tunnel was a common condition. But wet conditions are not unique

to the Howard Street Tunnel. A report by the Transit Cooperative Research Program16

states: 

The number one problem affecting tunnels and underground structures is 

groundwater intrusion and the subsequent damage caused by the presence 

of tunnel leaks. This groundwater intrusion is responsible for more 

problems affecting a tunnel’s concrete liners and steel reinforced concrete 

than all other tunnel structural problems combined. 

It is not known how much of the water intrusion in the Howard Street Tunnel comes from 

water supply lines, storm sewers, and other sources. 

The USACE postaccident geotechnical evaluation showed multiple structural

anomalies, including voids and delaminations behind the tunnel walls and within the 

 16 Transit Cooperative Research Program, Inspection Policy and Procedures for Rail Tunnels and 

Underground Structures (Washington, DC: National Academy Press, 1997). 

 14 NTSB/RAB-04/08
walls themselves. The timing of the voids’ development could not be determined with 

reasonable certainty. 

The CSX tunnel inspection procedures and documentation were neither thorough 

nor detailed. 

On July 23, 2001, a team of about 25 people who were, according to CSX, mostly 

engineers, entered the Howard Street Tunnel to perform an inspection to determine the 

tunnel’s structural integrity. The team included engineers from CSX and representatives 

of the city of Baltimore, the Maryland Transit Administration, and other organizations.

The team split into smaller groups to examine the sides and ceiling of the tunnel. A lift 

truck was used to allow close inspection of the tunnel ceiling. After the inspection, CSX 

determined that the tunnel was structurally sound. A follow-up inspection was performed 

on August 27, 2001. Again, no structural problems were found. 

On July 28, 2001, CSX had an engineering firm conduct two soil borings at the 

intersection of Lombard and Howard Streets, near the 40-inch water main found broken 

above the Howard Street Tunnel. To obtain core samples of the tunnel ceiling in the area 

of the water main, test bores were made through the street above the tunnel and into the 

brick lining of the tunnel ceiling about 10 feet to either side of the water main. The core

samples of the brick lining indicated that the brick and mortar were solid. 

Planning and Coordination 

CSX and City of Baltimore Coordination 

During the course of the investigation, it became apparent that information about 

modifications and construction in or near the tunnel had not been reliably documented or 

exchanged among interested parties. For example, there was an opening in the tunnel’s 

arch immediately below the 40-inch water main where a repair had at least been started.

Safety Board investigators attempted to obtain information about this void and repair, but 

neither CSX nor the city of Baltimore knew of or had documentation about when the void

was first discovered or who had initiated the repair. 

In another instance, information used by the city of Baltimore indicated that a

storm sewer was 19 feet below the surface near a test drilling. However, during the 

drilling project, the drill struck the storm sewer, which was actually only about 8 feet 

below the surface. Also during the drilling project, it was discovered that a manhole had 

been moved and the move was not documented. 

Documentation and information regarding construction and other alterations to 

the infrastructure in proximity to the Howard Street Tunnel are unreliable, and the 

exchange of such information between CSX and the city of Baltimore is inadequate. CSX 

railroad structures, portions of the Maryland Transit Administration light rail system and 

 15 NTSB/RAB-04/08
the Metro subway, and municipal and private utility lines and structures all coexist within 

a relatively compact area around the tunnel. Repairs and modifications to structures and 

utilities near the tunnel could have a significant effect on the tunnel’s structural integrity 

and therefore on the structures of other nearby facilities. 

Transportation of Hazardous Materials Through the Tunnel 

During the derailment, a tank car released more than 28,600 gallons of 

tripropylene. The flammable tripropylene was ignited, and the subsequent fire led to the

ignition of paper and wood products in adjacent freight cars. The burning wood and paper 

products sustained the fire over the next several days. The release of the tripropylene 

initiated the fire and increased the severity of the accident. 

Immediately behind the ruptured tripropylene car were two tank cars containing 

hydrochloric acid and one tank car loaded with di(2-ethylhexyl) phthalate, which is an 

environmentally hazardous substance. Exposure of the hydrochloric acid tank cars to high 

temperatures for the duration of the fire resulted in thermal degradation of the cars’

rubber linings and corrosive penetration of one of the cars by the acid. 

The CSX route through Baltimore and the Howard Street Tunnel is a major rail 

artery and is a designated hazardous materials key route for all types and classes of 

hazardous materials. Congress recognized the significance of this rail route when it 

mandated that the DOT conduct a rail infrastructure study17 for passenger and freight 

routes in the Baltimore corridor. Although the FRA had not completed the final report for 

the study as of August 2004, it has indicated that three options for improving the freight 

infrastructure through Baltimore have been considered. All three options involve the 

construction of new, modern tunnels with estimated costs ranging from $1 billion to

$3 billion. Because of the scope and expense of these options, replacement of the Howard 

Street Tunnel is not assured, and at best, several years will be required to complete such a 

project. 

Given these factors, improving the safety of the transportation of hazardous 

materials through the Howard Street Tunnel and minimizing the potential for more 

serious hazardous materials incidents in the tunnel will, in the Safety Board’s view, 

depend upon shared communication and coordination between CSX and the city of 

Baltimore about the volumes and types of hazardous materials that are transported

through the tunnel, anticipation of the types of incidents that might occur, and the 

capabilities and/or limitations of the city to access the tunnel and respond to any 

hazardous materials incident in it. The desired level of communication and coordination 

can be achieved through comprehensive emergency preparedness planning, including 

joint drills and exercises.

 17 U.S. Department of Transportation’s Baltimore, Maryland, Freight and Passenger Infrastructure 

Study, per Public Law 107-87. 

 16 NTSB/RAB-04/08
Emergency Preparedness Documents 

Emergency preparedness documents compiled by the Baltimore Office of Disaster 

Control and Civil Defense that were reviewed by Safety Board investigators do not 

contain information on hazardous materials discharge response procedures specific to

tunnel environments or infrastructure information on the Howard Street Tunnel. 

Although principals of the Baltimore City Fire Department and of the member

organizations of the South Baltimore Industrial Mutual Aid Plan, Inc.,18 told the Safety

Board that their personnel were familiar with response procedures applicable to tunnel 

environments and with the infrastructure of the Howard Street Tunnel, such information 

was not in the written plans. 

Investigators reviewed the existing Hazardous Materials Action Plan for the city 

of Baltimore. Although the plan had detailed infrastructure response information on 

virtually all the industrial facilities within the city of Baltimore, it did not have any 

information on the Howard Street Tunnel, which could easily present situations as 

dangerous to responders as some of the industrial facilities that are addressed in the plan. 

Despite the representations of the Baltimore City Fire Department and the South 

Baltimore Industrial Mutual Aid Plan, Inc., organizations that their employees were 

familiar with the Howard Street Tunnel, during the emergency response, the CSX 

dispatcher had to tell responding fire department personnel where to find a street-level 

manhole access to the tunnel at the intersection of Howard and Lombard Streets. The fire 

department later determined this access point to be instrumental to the fire suppression 

effort. 

Baltimore officials told the Safety Board that they had initiated revisions of their

Emergency Response Plan and Emergency Operations Plan to address a number of issues 

that were identified during the tunnel incident. The city has not yet provided the Safety 

Board specific information on the expected revisions. 

It has long been known that emergency responders should be provided with 

comprehensive information to effectively and efficiently discharge their emergency 

response duties. This is particularly true for those responding to hazardous materials 

incidents. The information should include not only specific emergency response 

protocols for addressing hazardous materials discharges that occur in a conventional 

(outdoor) environment but also protocols for discharges that occur in an unusual 

 18 The South Baltimore Industrial Mutual Aid Plan, Inc., is an association of private industries and 

government agencies with the primary purpose of providing “a system of cooperative action whereby 

assistance to the public sector and other member companies may be available in an emergency....” It has a

membership of about 88 active private industrial facilities in the greater Baltimore area. Members provide

technical maintenance support for periodically updating the city of Baltimore’s Hazardous Materials

Action Plan, contribute technical expertise, foster emergency preparedness, and render mutual aid in the

event of an emergency involving hazardous materials. 

 17 NTSB/RAB-04/08
environment, such as inside a tunnel or on a long bridge at night, where conventional 

response protocols might not apply. 

Emergency preparedness plans to address incidents within a tunnel environment

could include, for example, considerations of the infrastructure, such as ambient 

ventilation, possible water infiltration, natural drainage, service and emergency lighting, 

emergency equipment, and personnel access, among other types of information that 

would not necessarily apply to an outdoor incident. Having such information clearly 

documented and instantly available is critical not only for experienced emergency

responders but also for new emergency response recruits or support personnel unfamiliar 

with tunnel environment emergency response procedures. 

The Baltimore City Fire Department told investigators that the department 

intended, at some future date, to coordinate with CSX to revise and update the

department’s Manual of Preparedness and training manuals to include infrastructure 

information on the Howard Street Tunnel and its potential access sites. Department

officials also said they plan to revise and update their firefighter recruit training and to 

include periodic practice drills appropriate to the Howard Street Tunnel. 

Environmental Response and Impact 

The environmental response by the Maryland Department of the Environment and 

U.S. Coast Guard Activities Baltimore was timely and effective. The Maryland

Department of the Environment quickly mobilized its hazardous materials spill response 

team to perform a site assessment. Within 3 hours of the accident, Coast Guard Activities 

Baltimore had dispatched a field response team to assist the State and local incident 

command and had established two safety zones because of the potential threat from 

hazardous vapors. Both agencies effectively coordinated with each other and with CSX 

environmental contractors to ensure that water sampling and air monitoring were 

conducted in a timely manner. 

Following the excavation of slightly more than 1,400 tons of soil and debris from 

the tunnel, no appreciable amounts of hydrochloric acid or tripropylene residues were 

found in the soil in the tunnel. Also, following the removal of 3,000 gallons of water and 

product from the city’s storm drains in response to reports of chemical odors during the 

weekend of August 11 and 12, 2001, no additional chemicals (other than residual traces) 

were found in the storm drain system. 

Probable Cause 

The National Transportation Safety Board, after an exhaustive investigative

effort, could not identify convincing evidence to explain the derailment of CSX freight 

train L-412-16 in the Baltimore, Maryland, Howard Street Tunnel on July 18, 2001. 

 18 NTSB/RAB-04/08
No preaccident equipment defects or rail defects were found. Computer

simulations were used to evaluate locomotive event recorder data, train profile data, track

profile data, and preaccident track geometry data. These simulations indicated that 

neither train operations nor changes in track conditions alone likely resulted in a 

derailment. Available physical evidence and computer simulations also showed that the 

most likely derailment scenario involved an obstruction between a wheel and the rail, in 

combination with changes in track geometry. However, postaccident fire, flooding, and 

necessary emergency response activities, including removing burning freight cars from 

the tunnel, significantly disturbed the accident site; and, no obstruction was identified that 

could be convincingly connected to wheel climb and evidence was insufficient to 

determine changes in track geometry. 

Recommendations 

As a result of its investigation of the Howard Street Tunnel railroad accident, the 

National Transportation Safety Board makes the following safety recommendations: 

To CSX Transportation, Inc.: 

Maintain historical documentation of maintenance and inspection 

activities affecting the Howard Street Tunnel. (R-04-13) 

Take action necessary to enhance the exchange of information with the 

city of Baltimore on maintenance and construction activities within and in 

the vicinity of the Howard Street Tunnel. (R-04-14) 

To the city of Baltimore, Maryland: 

Take action necessary to enhance the exchange of information with CSX 

Transportation on maintenance and construction activities within and in 

the vicinity of the Howard Street Tunnel. (R-04-15) 

Update and revise your emergency preparedness documents to include 

information on hazardous materials discharge response procedures 

specific to tunnel environments, as well as infrastructure information on 

the Howard Street Tunnel. (R-04-16) 

 19 NTSB/RAB-04/08
BY THE NATIONAL TRANSPORTATION SAFETY BOARD 

Ellen Engleman Conners 

Chairman

Mark V. Rosenker 

Vice Chairman 

Carol J. Carmody

Member 

Richard F. Healing 

Member 

Deborah A.P. Hersman

Member 

Adopted: December 16, 2004 

Deborah A. P. Hersman, Member, filed the following concurring opinion on 

December 1, 2004. Richard F. Healing, Member, joined Member Hersman in this 

opinion. 

Mark V. Rosenker, Vice Chairman, concurred in part, filing the following 

statement on December 16, 2004: 

While I concur in most of the sentiments offered by Member Hersman, I 

do not believe the need for additional safety recommendations is 

demonstrated, nor am I convinced that NTSB access to the scene was

imprudently delayed. 

Notation 7662 

Member HERSMAN, concurring:

Despite having many reservations, I have agreed with my colleagues to 

release this accident brief without having a Board Meeting because no

probable cause was determined and this investigation is now over three

years old. Considerable Safety Board resources have been dedicated to 

this accident investigation and we have little to show for it. While there 

are several issues I think could have been raised in a public forum, given

the tardiness of this brief and the lack of findings, holding a Board 

Meeting would not likely change the outcome of the brief or our

recommendations. Moreover, I have been advised that it would be a drain 

 20 NTSB/RAB-04/08
on staff resources to prepare for such a Board Meeting. As such, I will 

instead raise the following issues, which I believe should be 

acknowledged with respect to this accident investigation: 

1.) The four recommendations contained in the brief could have been 

made within one month of the accident. While there was no probable 

cause determination in this accident, there were significant issues raised

during the investigation. I believe we should have made additional 

recommendations to the Department of Transportation (DOT) and the 

Department of Homeland Security (DHS). (See attachment.) 

The Federal Railroad Administration (FRA) has no requirements for the 

inventory and inspection of tunnels. While railroad tunnels are generally 

built to last,1

 this seems to be an area where federal guidance is lacking.

There are federal requirements to inspect the track, the equipment, and 

railroad bridges, but nothing addressing tunnels. As major railroad tunnels 

age, the potential risks of problems increase if maintenance is deferred. 

Many major tunnels in urban areas are over one hundred years old and still 

heavily utilized.2

 Following the accident, there were many documented 

areas of concern in the tunnel, with little information provided on the

inspection and maintenance of the tunnel structure. 

Accompanying my concerns regarding the condition and maintenance of 

railroad tunnels is the safe transport of hazardous materials through them. 

While the transport of hazardous materials has been a principal security 

concern, it should also be addressed as a safety issue. The Department of 

Transportation and the Department of Homeland Security are drafting 

studies and soliciting comments on the transportation of hazardous 

materials. Generally, the record shows that transporting hazmat is safer on 

the rails than on the highway. For example, in 1997, the most recent year 

in which we have data for the transportation of hazardous materials by 

mode, trucks and trains both moved approximately 75 million ton miles of 

hazardous materials.3

 However, there were 11,932 incidents and 12 deaths 

on the highway contrasted with 1,102 incidents and no deaths on the 

railways. 

 1

 As evidenced by the robustness of the Howard Street Tunnel that survived the derailment, explosion,

subsequent fire and flooding and remains in service today.

2

 For example, CSX’s Howard Street Tunnel was constructed from 1890 to 1895 and is the only northsouth freight route east of Hagerstown, Maryland. Amtrak owns the First Street tunnels from the Virginia 

Avenue interlocking to Union Station in Washington, D.C., which date back to 1904 and are used by

Amtrak and the Virginia Railway Express. Amtrak also owns the B & P tunnel in Baltimore built in 1872, 

which is used by the Maryland Transit Administration, as well as tunnels used by New Jersey Transit 

commuters and Amtrak intercity passengers under the Hudson and East Rivers between New Jersey and

New York.

3 Commodity Flow Survey, U.S. Department of Transportation, Bureau of Transportation

Statistics/U.S. Department of Commerce, Economics and Statistics Administration, U.S. Census Bureau

(1997). 

 21 NTSB/RAB-04/08
In short, the consideration of safety and security issues is often 

inextricably linked. While critical infrastructure and concerns about the 

transport of hazardous materials are central themes in current public 

debate surrounding security concerns, the only experience we have to date 

shows that they should be regarded as important safety issues. Given the 

long history of expertise at the Federal Railroad Administration in dealing 

with rail safety issues, including transportation of hazardous materials, it is 

imperative that any decisions made by DHS with respect to security 

measures also take into account relevant safety considerations. 

2.) Three years have passed since the accident. In an accident

investigation, much of what is important to the community, the industry, 

the employees, and in some cases, the victims, is identifying what

happened, and for the parties involved to take actions to prevent such an 

accident from occurring again. I acknowledge that it is harder and more 

time consuming to prove all of the things that didn’t happen. In this 

accident, significant time was spent ruling out possible accident scenarios

because a probable cause with contributing factors was not determined 

early in the investigation. While I understand that a backlog of accident 

investigations has been eliminated in the last several years, there needs to 

be a renewed focus on timeliness and clear expectations about the process. 

Three years is simply too long to spend on a brief without making 

significant progress on the cause or recommendations. 

A review of the docket shows that the bulk of the work on this 

investigation was completed by April of 2003, including much of the 

written brief. While all of the staff involved in this investigation worked 

diligently to determine the cause of the accident and make appropriate

recommendations, a great deal of time was spent in administrative review, 

including two months in my office. If the delays are a result of the lack of 

staff resources, which compromise our ability to launch on accidents and 

complete our investigations in a timely manner, then a revised timetable

ought to be established based on the resources available and all parties 

should be advised of what to expect. 

3.) Lack of access to the accident scene severely compromised our ability 

to determine the probable cause. This was a unique accident in that much 

of the evidence was removed or disrupted because of the postaccident fire 

and subsequent flooding, which resulted in a significantly disturbed 

accident scene. The emergency response efforts clearly were the first 

priority in the hours after the accident, as they should be. However, it was

almost two days before NTSB personnel entered the tunnel to assess the 

accident scene. If we do not have access to the scene in a timely manner, 

then we cannot assess damage and document the evidence. In the future, it 

is important to be among the first to access the accident scene as soon as it

is safe to do so and ensure that other parties do not disturb the evidence. 

 22 NTSB/RAB-04/08
4.) Lastly, there are general concerns, as there are in any accident

investigation, about the resources available to staff. We have only 13 rail 

investigators at the Safety Board, working on freight rail, passenger rail, 

and transit accidents. Additionally, as in most of the accidents investigated

by the Safety Board, we had to rely on parties to the investigation to

provide significant support for our work. In this accident, we had to rely 

on the Association of American Railroads (AAR) to provide access to 

simulation software to model the accident. In this case, there was not 

another option, and to my knowledge, our reliance on the AAR did not 

pose a problem; however, it is worth noting potential drawbacks that may 

affect future investigations, i.e. constrained staff resources, a limited 

number of experts and the necessity of relying on outside sources for 

technical support.

 23 NTSB/RAB-04/08
Attachment to Concurring Opinion of Member Hersman 

To the Federal Railroad Administration: 

Work with tunnel owners to assess the safety of major railroad 

tunnels and provide guidance to tunnel owners and users regarding 

inspections, maintenance intervals and documentation. 

In the aftermath of the CSX freight train derailment and 

subsequent fire in the Howard Street Tunnel, several important issues need 

to be addressed regarding the maintenance and repair of railroad tunnels. 

While maintenance issues may not have been a causal factor in the 

Howard Street Tunnel accident, incomplete and inaccurate information 

regarding recent construction and repairs to the tunnel’s infrastructure 

represents a serious deficiency in record-keeping as well as an inability to 

adequately assess the conditions in the tunnel and exchange such 

information with other interested parties. As indicated in the brief,

investigators could not locate any CSX records detailing the extent or

nature of recent repairs and modifications to the tunnel over the years. 

This absence of maintenance and repair documentation highlights the need 

for comprehensive and systematic assessment and management of railroad 

tunnels that will accurately and reliably record this information and allow 

for its exchange between railroad personnel, tunnel owners, emergency 

response organizations, oversight agencies/administrations, and other 

interested parties. 

Given the current state of information available on railroad tunnels, 

the inadequacies uncovered in the Howard Street Tunnel accident are not 

likely an isolated incident of poor record keeping by CSX. After 

conducting preliminarily searches, including requests to the FRA and the 

AAR, for the data on the number, age, condition, maintenance, and 

inspection of railroad tunnels, it appears that this information is not easily 

accessible or even available. Moreover, access to existing data is further 

complicated by its dispersion across a number of different sources. In 

contrast, a good deal of information is provided for road and rail transit 

tunnels. The Federal Transit Administration (FTA) and the Federal 

Highway Administration (FHWA) joined forces in March 2001 to create a 

comprehensive Tunnel Management System4

 for all road and rail transit 

tunnels in the U.S. With the goal of implementing uniform maintenance

and rehabilitation practices to reduce the dangers associated with poor 

inspection procedures and deferred repairs, a system was implemented that 

provided for standardized assessments, inspections, and maintenance

regulations. Additionally, a computerized database for collecting and 

 4

 See Highway and Rail Transit Tunnel Maintenance and Rehabilitation Manual (FHWA and FTA 

2003). 

 24 NTSB/RAB-04/08
storing all inventory, inspection, and repair data was created. By adopting 

uniform condition codes and prioritizations for repairs and establishing set 

frequencies for inspections, the FTA and FHWA have taken the necessary 

steps to insure adequate reporting, recording, and storage practices for 

both inventory and maintenance of road and rail transit tunnels. 

While still in its infancy, this system promises a number of 

important advantages. Specifically, an effective management program, 

“will help tunnel owners and operators all across the country identify 

potential problems within their tunnels and will provide guidelines for 

proper maintenance to extend the life of a tunnel and/or to avoid more

costly problems later.” Furthermore, this system “can minimize damage, 

disruption of service, and traffic delays caused by typical tunnel problems 

such as those caused by groundwater and inadequate ventilation.”5 And 

perhaps most importantly, the creation of a centralized inventory and 

inspection database will allow for the storage and exchange of tunnel 

infrastructure information that can aid emergency responders and help 

reduce the future loss of life and environmental damage associated with 

these accidents.

As evidenced by the NTSB factual brief on the conditon of the 

Howard Street Tunnel,6

 the Army Corps of Engineers postaccident study 

on the structural concerns,7

 and the presence of water around the tunnel, a 

number of significant safety issues exist.8

 It is generally accepted that the 

biggest single problem affecting all tunnels is damage caused by water 

infiltration. According to the Transit Cooperative Research Program 

report, “Groundwater intrusion is responsible for more problems affecting 

a tunnel’s concrete liners and steel-reinforced concrete than all other 

tunnel structural problems combined.”9

 Concrete spalling and 

delamination, in turn, trigger a new set of complications that may make 

the tunnel unusable. Uncontrolled water can potentially cause electrical 

shorts and other dangerous situations. Therefore, adequate drainage and 

clearance of water from the tunnel and right-of-way is a major 

maintenance consideration.10

 5 A Light at the End of the Tunnel, Frank V. Botelho, (FHWA 2003).

6

 National Transportation Safety Board, Factual Brief on Howard Street Tunnel Construction and

Condition, Dr.Joe Kolly, Group Chairman, January 7, 2003. 

7 Engineering and Geotechnical Report, U.S. Army Corps of Engineers (December 31, 2002). 

8

 These studies address several important structural concerns, e.g., holes in the south wall, brick and 

mortar conditions, arch damage near Lombard Street, spalled brick lining, etc.

9

 Inspection Policy and Procedures for Rail Transit Tunnels and Underground Structures, TCRP

Synthesis 23. 

10 See Highway and Rail Transit Tunnel Maintenance and Rehabilitation Manual (FHWA and FTA 

2003). 

 25 NTSB/RAB-04/08
Unlike the highway and transit tunnels which are often publicly

owned and financed by taxpayer dollars, the private freight railroad 

industry owns almost all of the railroad infrastructure in the United States. 

However, all of the railroads’ assets coexist with the public, as is

evidenced by the impact of the CSX tunnel accident in July 2001 on the 

city of Baltimore. In many cases, what occurs on a private right-of-way 

may have significant consequences to the general public. 

While the list of activities and expenditures required to keep a 

tunnel in good, safe working condition is long, at a minimum, the FRA 

should provide guidance on inspections and record-keeping. While the 

private sector has long understood the asset management process, the fact 

that no records exist about inspections, structural damage or repairs made 

to the Howard Street Tunnel raises significant questions about how 

determinations could be made to predict future performance and decisions

for maintenance activities and capital improvement projects. The FRA 

should work with the railroad industry to assess the current state of major 

railroad tunnels and address the inspection and maintenance of tunnels. 

To the Department of Transportation and the Department of 

Homeland Security: 

Complete ongoing studies and rulemaking efforts to address the 

transportation of hazardous materials and coordinate future 

activities. 

Highlighting the risks associated with the transport of hazardous 

materials through tunnels, the Howard Street Tunnel accident raises

several important safety issues. First, is the need to develop a more 

comprehensive risk analysis system to assess the dangers associated with 

the transport of specific materials. Second, is the implementation of 

detailed emergency preparedness plans and appropriate training for rail 

employees and emergency responders. Third, is the implementation of 

standardized regulations for governing the transport of dangerous goods. 

There are more than 240,000 tank cars in the North American 

railroad car fleet and rail shipment of hazardous materials accounts for 18

percent of the ton-miles of all hazardous materials shipped. In 2000, 725 

of the reported railroad accidents involved trains transporting hazardous 

materials. Out of 6,942 cars in those trains, 979 of the cars were damaged 

and 75 cars released hazmat. This resulted in 5,251 people being 

evacuated. One fatality (a result of the accident, not due to a hazmat 

release), 82 injuries, and over $26 million in property damage were 

reported. Therefore, even with the great safety improvements made to tank 

 26 NTSB/RAB-04/08
cars in the 1970s, 1980s, and 1990s, hazmat is still released during 

accidents.

11

Currently, the FRA is undertaking three major projects designed to 

improve the safe transport of hazardous materials by rail.12 The first of 

these projects, Hazmat Transportation Safety, has the goal of enhancing 

the safety and efficiency of transporting dangerous materials by rail. To

accomplish this goal researchers are investigating the shipment routing of 

hazardous materials, specifically considering the confinement of hazmat

transport to certain “classes” of tracks and rerouting dangerous shipments 

around major metropolitan areas. A second project, Tank Car Structural

Integrity, is charged with the goal of ensuring that the capability of hazmat 

carriers to maintain structural integrity is understood. Safety issues 

considered by this ongoing project include the following components and 

elements related to overall tank car integrity: fatigue damage, welding 

effects, puncture resistance, steel quality, and thermal protection systems.

The third project, Damage Assessment and Improved Inspection Systems, 

is intended to develop, improve, and quantify the capability to assess the 

condition of tank cars, in repair shops and at accident sites. In particular,

the project is designed to increase safety by improving assessment of 

damaged tank cars and enhancing the existing inspection and repair 

process. Additionally, it is expected to reduce postaccident risk to 

emergency responders by providing them with critical information about 

tank car condition.13

In addition to the FRA’s efforts to increase safety, recent actions 

have focused on improving the security of rail transportation, with much 

remaining to be done. Presidential Decision Directive (PDD) 63, “Critical 

Infrastructure Protection,” requires federal agencies to “take all necessary 

measures to swiftly eliminate any significant vulnerability to both physical 

and cyber attacks on our critical infrastructures, including especially our 

cyber systems.” Rail transportation has been determined to be a part of the 

nation’s critical infrastructure. Recently, the DOT’s Research and Special 

Programs Administration and DHS’s Transportation Security 

Administration published a notice in the Federal Register14 soliciting

comments on measures to enhance the security of rail shipments of toxic 

inhalation hazardous materials. The comment period closed on October

 11 Federal Railroad Administration Website. 

12Railroad Research and Development Program (Chapter 4, Sec. 4.8)

<http://www.fra.dot.gov/us/content/1242>. 

13 By supplying emergency responders with up-to-date, detailed information about the condition of

tank cars, the FRA hopes to avoid another tank car accident like the one in Waverly, Tennessee, in the

1970s that resulted in the death of a number of emergency responders when a tank car ruptured

unexpectedly due to an undetected crack. 

14 Federal Register, Vol. 69, No. 157, Monday, August 16, 2004, Notices, pages 50988-50994. 

 27 NTSB/RAB-04/08
18, 2004 and the NTSB submitted comments for the record.15 At this time 

no further action has been taken on this notice. 

A serious incident involving the transport of dangerous goods in a 

tunnel can be very costly in terms of human lives, the environment, tunnel 

damage and transport disruption. However, a decision to completely ban 

the transport of hazmat by rail could increase the overall societal risk of 

hazmat accidents by diverting the shipment to even less safe modes of 

transport. Simply redirecting the shipment of hazmat to alternative modes 

of transport or rerouting it around densely populated areas does not solve 

the above safety concerns. In many cases, the highest quality of track may 

go through major metropolitan areas, and unlike roads there are not 

generally bypass tracks around these areas. Moreover, additional 

switching and interchanges employed to avoid tunnels and metropolitan

areas has inherent risk. 

Reducing transportation risk should be the objective; however, 

quantification of risk is difficult because numerous factors and variables 

influence probabilities and consequences of incidents involving dangerous

goods both inside and outside of tunnels. Even with expert knowledge, it 

is therefore difficult to assess risk for all circumstances, environments, 

conditions, etc. In order to rationally evaluate the risks and set regulations, 

current studies and rulemaking activities need to be completed and 

evaluated. I would urge the DOT and DHS to complete their ongoing 

efforts as soon as possible and coordinate their future activities to address 

security AND safety. 

 15 National Transportation Safety Board correspondence, Hazardous Materials: Enhancing Rail

Transportation Security for Toxic Inhalation Hazard Materials, Notation 7672 (10/13/2004). 

 28 NTSB/RAB-04/08