E PLURIBUS UNUM

NATIONAL TRA SPORTATION

B OARD

SAFE T Y

N

National Transportation Safety Board 

Washington, D.C. 20594

Railroad Accident Brief

Accident No: DCA-02-FR-013 

Railroad: Norfolk Southern Railway 

Train: Train 15T

Location: Farragut, Tennessee

Accident date and time: September 15, 2002, 11:20 a.m. eastern daylight time 

Type of Accident: Derailment 

Fatalities/Injuries: No fatalities or serious injuries 

Property Damage: $1.02 million 

The Accident 

About 11:20 a.m. eastern daylight time on September 15, 2002, westbound 

Norfolk Southern Railway (NS) train No. 15T derailed in Farragut, Tennessee, while 

moving at 38 mph. The train was made up of 3 locomotives, 56 loads, and 86 empties; a 

total of 142 cars with a gross weight of 9,948 tons. Two locomotives and the first 25 cars

derailed. A tank car containing sulfuric acid was punctured, releasing a cloud of toxic 

fumes that prompted local responders to evacuate about 2,600 people from a 4.4-square 

mile area around the site. The evacuation lasted for about 2 1/2 days. Several local 

residents were treated for minor respiratory difficulties. There was no fire. Damages were 

estimated to be $1.02 million. (See figure 1.) 

At 8:30 a.m., about 2 hours 50 minutes before the derailment, eastbound NS train 

No. 721, en route to Knoxville, Tennessee, passed over the spring switch1

 from the Boyd 

Siding onto the main track. About an hour later, eastbound train No. 703 received an 

unexpected restricting signal indication2

 at the west end of Boyd Siding, which is about 2 

 

1

 A spring switch is a switch equipped with a spring mechanism arranged to restore the switch points

to their normal positions after they have been temporarily repositioned by the passage of a train. In the case 

of the East Boyd Siding, the switch was normally lined for movement along the main line. But the wheels 

of a train moving onto the main line from the siding would cause the switch points to move into alignment

for that movement without the need for a crewmember to throw the switch. After the train had cleared the

switch, spring pressure would realign the switch for the main line. 

2 With no traffic in the track block immediately ahead of train 703, the signal was expected to display a 

clear aspect. 

1 NTSB/RAB-03/05 
miles from the east end of Boyd Siding. This signal indication required that the crew slow 

the train from the normal track speed of 50 mph to a speed, not to exceed 20 mph, that

would allow the train to stop within half the visual range and short of any obstructions. 

The train crew reduced the train’s speed and reported the signal indication to the train 

dispatcher, as the operating rules required. 

Figure 1. Looking east at the derailment of NS train 15T showing fuming sulfuric acid from

ruptured tank car. 

At the east end of the siding, the crew of train 703 stopped short of the spring 

switch so the conductor could look at the switch before proceeding. He found that the left

switch point (when facing west) was not seated tightly against the stock rail but instead 

had a 1/4-inch gap.3

 A spring switch can be thrown manually by moving a lever beside 

the track. After operating the spring switch through its motion several times, the 

conductor found that the left switch point still failed to close completely, leaving about a 

1/8-inch gap between the switch point and the stock rail. (See Figures 2 and 3.) 

 

3

 Such a gap could cause the wheel flange of a westbound train to strike the end of the switch point, thereby damaging the switch or causing a derailment. The gap would also account for the restricting

indication the crew had received from the automatic block signal. 

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Figure 2. Gapped switch point. 

Figure 3. Spring switch similar to the East Boyd Siding switch where derailment

occurred. Switch is aligned for main line movement. 

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The engineer of train 703 radioed the train dispatcher and reported that the switch 

points had not lined “back all the way to line up for the main line; you might need 

somebody to look at it.” The dispatcher replied, “Alright, I’ll get somebody headed that 

way.” Because an eastbound train movement was a trailing movement4 that would tend to 

force the switch points back into the correct position, train 703 proceeded through the 

switch without incident. 

About 9:45 a.m., just after train 703 had cleared the switch, the train dispatcher 

called a signal maintainer to inspect the spring switch. The dispatcher advised the signal 

maintainer that he did not have to hurry because no trains were due to arrive at the switch

soon. The maintainer ate breakfast and departed his home at about 10:20 a.m., arriving at 

the switch at about 11:00 a.m. The signal maintainer said that as he approached the 

switch, he could see the signal controlling westbound train movements and noted that it

was showing a clear aspect, indicating that the switch gap had closed after train 703’s

movement over it. 

The signal maintainer said that when he arrived at the switch, he noted that the 

points appeared to be properly positioned. He said that he visually inspected the switch 

and noticed that the switch plates,5

 while not really dry, “looked like they could use a 

little oil.” He said that he put oil on each switch plate. He walked from the heel block to 

the switch point and did not see anything unusual. (See Figure 4.) 

In order to make an internal inspection of the switch to determine why the spring 

switch had gapped, the signal maintainer was required to get a track warrant to occupy 

the track and inspect the mechanical movement of the switch. The signal maintainer

called the train dispatcher and told him that the switch appeared to be aligned properly 

and asked about a track warrant and any expected train traffic. The dispatcher told the 

signal maintainer that a freight train (train 15T) and a coal train were en route toward the 

switch. The signal maintainer replied, “Okay, all right, I will wait till these two [trains]

get by [the switch] and holler at you.” 

The signal maintainer, while waiting on the north side of the main line adjacent to

the switch, heard the crew of train 15T call out the clear signal at east Boyd. According to 

event recorder data, train 15T approached the switch at about 38 mph.6

 The engineer 

stated that as the locomotives moved over the switch, he felt a slight “tug,” and he, along 

 

4

 The east Boyd siding switch was oriented such that eastbound trains would make trailing movements 

through the switch; that is, they would enter the switch at the opposite end from the moveable switch

points. Westbound trains would make facing movements; that is, they would reach the switch points first as 

they entered the switch. 

5

 Switch plates are between the switch points and the crossties and are elongated tie plates. The

movable switch points rest on the switch plates. 

6

 Even though the authorized track speed at this location was 50 mph, train 15T was restricted to 45

mph because of a dimensional load (two U.S. Army tanks). 

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with the conductor, looked back and saw the train starting to derail. The train went into 

emergency braking at that time. The engineer said he immediately saw what appeared to 

be a smoke cloud coming from the train. The engineer radioed the train dispatcher by 

using the emergency 911 radio tone and advised him of the derailment and of the smoke. 

The signal maintainer also called the dispatcher, about 11:20 a.m., to report the 

derailment. 

Figure 4. Diagram of a switch and turnout 

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NS had no specific procedure that required a functional test of a spring switch on 

a trouble call. The NS monthly and quarterly switch inspections (detailed in NS 

procedure MS 1914) require that the switch points be opened and the switch operated in 

both directions. The Federal Railroad Administration (FRA) minimum safety 

requirements for railroad track in 49 Code of Federal Regulations 213.135(b) also specify 

that each switch point shall fit its stock rail properly. The signal maintainer’s initial visual 

examination did not reveal a problem, but he did not operate the switch before train 15T

passed over it. NS operating rules did not specify that an inspection of a possibly 

defective switch should be completed before trains are allowed to operate through the 

area. NS procedures also did not address the reduction of train speeds after receiving a 

trouble call about the condition of a switch. 

The train dispatcher summoned local police and emergency response personnel, 

who began arriving on the scene within 5 minutes of the derailment. The conductor’s 

train inspection had revealed that the smoky cloud was fuming sulfuric acid escaping 

from the 18th car. As soon as the emergency personnel arrived, the conductor discussed 

the train consist with them. After considering the potential effects of the hazardous 

material spill, responders began evacuating the residential subdivisions surrounding the 

accident site. 

NS dispatched emergency hazardous material cleanup crews to the site 

immediately after the derailment, and the cleanup was underway within several hours. 

The contractors placed soda ash and lime on the leaking sulfuric acid to neutralize it. NS 

and local officials constantly monitored air quality until the evacuation order was ended. 

Postaccident inspection of the East Boyd spring switch revealed that a bolt was 

missing from the No. 4 throw rod. The missing bolt was 4 3/4 inches long and 3/4 inch in 

diameter. During the inspection, a 2 7/8-inch-long piece of the head section of what was

believed to be the missing bolt was found approximately 80 inches back from the switch 

point, lodged between the base flanges of the left switch point rail and the left stock rail. 

(See figure 5.) 

The head section of the switch throw rod bolt and the base of the stock rail and 

the base of the switch point showed marks and abrasions that were evidence of the bolt 

being lodged and thus obstructing the normal alignment of the two rails. At this location, 

the broken bolt section could interfere with the movement of the left switch point rail 

(when facing west) and cause a gap between the switch point and the stock rail. Although 

the switch points could be forced into alignment by a train making a trailing (eastbound) 

movement over the switch, the interference created by the lodged bolt made the points 

susceptible to gapping if they were disturbed, such as by a train making a facing 

(westbound) movement over the switch. 

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Because the bolt section was lodged at the base of the closed rails, it was not 

visible with the switch positioned as it was when the signal maintainer arrived. When the 

switch is operated and the rail sections separate, the switch point rail moves about 4 to 4 

1/2 inches away from the stock rail. In this position, the heads of the throw rod bolts and 

the base of the rails are visible. The location of the missing bolt would also have been 

visible. 

Figure 5. Postaccident reconstruction of broken bolt section as positioned

before the derailment. 

Probable Cause 

The National Transportation Safety Board determines that the probable cause of 

the September 15, 2002, derailment of Norfolk Southern train 15T was (1) the decision 

by the train dispatcher and signal maintainer to allow the train to pass over the spring

switch at maximum authorized speed before the switch had been adequately inspected or 

clamped closed and (2) the lack of company procedures requiring that train dispatchers, 

after receiving a report of a problem involving a main track switch, immediately stop 

trains or implement an appropriate speed restriction in the affected area. 

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Recommendations 

As a result of its investigation of this accident, the National Transportation Safety 

Board makes the following safety recommendations: 

To the Federal Railroad Administration: 

1. Require that train dispatchers, upon receiving reports of potentially 

hazardous conditions involving a main track segment or switch, stop

train movements or immediately implement an appropriate speed 

restriction for the affected area and remove the restrictions only after 

the completion of those inspections and/or repairs that are essential for

the safe movement of trains. (R-03-4) 

To the Norfolk Southern Railway:

2. Require that your train dispatchers, upon receiving reports of

potentially hazardous conditions involving a main track switch, 

immediately stop train movements or implement an appropriate speed

restriction for the affected area and remove the restrictions only after 

the completion of those inspections and/or repairs that are essential for

the safe movement of trains. (R-03-5) 

Adopted: July 21, 2003 

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