RAB/98-23

NATIONAL TRANSPORTATION SAFETY BOARD

WASHINGTON, D.C.

Railroad Accident Brief Report

ATL97FR020

REAR-END COLLISION/DERAILMENT

CONRAIL

HUMMELSTOWN, PENNSYLVANIA

SEPTEMBER 29, 1997

On September 29, 1997, about 5:45 p.m. eastern daylight time, eastbound

Consolidated Rail Corporation (Conrail) train PIBE-8, consisting of 2 locomotive units

and 136 cars, passed a stop and proceed signal at 30 mph and struck the rear locomotive

unit of eastbound Conrail train ENS-103, consisting of 5 locomotive units. Train ENS103 was stopped at signal 1081E (milepost 104.2 at control point [CP] Tara) in

Hummelstown, Pennsylvania. Each train was crewed by a conductor and an engineer. The

conductor on train PIBE-8 sustained fatal injuries in the accident. No other injuries were

reported. Damages were estimated at $571,700. Weather conditions were clear, with

bright sunlight and a temperature of 65° F.

The train ENS-103 crew went on duty at 2:30 p.m. at Enola Yard near Harrisburg,

Pennsylvania. The crew picked up five locomotive units at the diesel shop and began a

trip to Oak Island Yard in Newark, New Jersey. According to event recorder data, the

train had been halted at a stop signal at 1081E for 28 minutes when the rear-end collision

occurred.

Train PIBE-8 departed Harrisburg about 4:15 p.m. en route to Allentown,

Pennsylvania. As the train approached signal 1061E, the signal was displaying a stop and

proceed (red over red signal aspect) indication.1

 The engineer stated that both he and the

conductor observed and called the signal as “approach medium” (yellow over green

signal aspect).2 The engineer said the train was traveling about 10 mph when he and the

conductor observed the signal; the engineer then allowed the train to increase speed to

about 30 mph, which would have been an appropriate response to an approach medium

signal. He stated that as train PIBE-8 came around the lefthand curve, he observed train

ENS-103 stopped at CP Tara. The train PIBE-8 engineer put his train into emergency

braking but was unable to stop short of train ENS-103.

 

1 This indication calls for the train crew to stop and then proceed at restricted speed.

2 An approach medium indication calls for the train crew to proceed to the next signal not exceeding

medium speed.
2

Postaccident tests revealed that signal 1061E, located about 2 miles west of signal

1081E, was coded to display a stop and proceed signal. The tests also confirmed that the

signals were properly wired. Postaccident inspection of signal 1061E revealed that the

stop and proceed signal was out of focus. Rusty water was found in the signal lens. When

viewed from the track, the signal was partially obscured by tree foliage.

On October 1, 1997, National Transportation Safety Board investigators, with

representatives of the Federal Railroad Administration, the Brotherhood of Locomotive

Engineers, the United Transportation Union, and Conrail, used a locomotive to replicate

the preaccident events. In sunny conditions, the test locomotive traveled eastbound

toward signal 1061E at the same time of day that the incident occurred. Signal 1061E was

set to display a stop and proceed signal.

When the test locomotive had moved to within about 1,500 feet of signal 1061E,

the signal could not be clearly distinguished by persons on the locomotive. As the

locomotive approached the signal more closely, the top aspect of the signal appeared to

be yellow and the bottom aspect appeared to be green. Eventually, as the locomotive

moved still closer to signal 1061E, the signal aspect could not be distinguished at all.

Persons on the test locomotive variously reported seeing yellow, red, and green aspects.

The out-of-focus condition of signal 1061E, in combination with the late

afternoon sun shining on the signal face and the water in the lens, probably made the

signal aspect appear to the train PIBE-8 train crew to be yellow over green instead of its

actual display, which was a red over red aspect. The result was a “phantom signal.” A

phantom signal is defined by the Association of American Railroads Signal Manual as

“an aspect displayed by a light signal, different from the aspect intended, caused by a

light from an external source being reflected by the optical system of the signal.”

PROBABLE CAUSE

The National Transportation Safety Board determines that the probable cause of

the accident was a phantom signal indication that resulted because the Consolidated Rail

Corporation failed to ensure that the signal aspects displayed could be properly seen by

train crews.

Adopted: December 1, 1998