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The collision occurred on a right-hand curve and the locomotive and caboose were deflected toward the right side of the track. The lead locomotive unit of train WA-4 turned over on its right side and came to rest perpendicular to the track. Although there was no override, both the caboose and the locomotive unit were extensively damaged. The five derailed cars of train WA-6 were driven across tracks Nos. 3 and 4 and were extensively damaged. The other derailed locomotive units and cars of train WA-4 were not extensively damaged. (See figure 2.)

The catenary was slightly damaged. About 210 feet of track No. 1 and 190 feet of track No. 2 were damaged.

Total damage was estimated to be about $300,000.

Train Information

The engineer of train WA-6 made the required locomotive inspection and tests at Potomac Yard, including the required airbrake tests on the entire train. The engineer reported a power loss on the locomotive en route and the dispatcher sent a helper locomotive to assist the train from Bowie, Maryland, to Bay. When the original locomotive units of WA-6 and the helper locomotive were replaced with two diesel-electric units at Bay, the engineer applied and released the train brakes; the test was observed only at the head end of the train. Because of the lack of radio communication with crewmembers at the rear of the train, the engineer was not informed about whether the brakes had applied and released on the rear car nor whether the air pressure was restoring at Notification of the results of airbrake tests is required by ConRail operating rules and Federal regulations. (See appendix B and 49 CFR 232.13.)

The engineer of train WA-4 visually inspected the four dieselelectric units and performed a cab signal test at Potomac Yard. He also tested the locomotive brakes. However, during this test, the engineer did not leave the cab of the lead unit and did not observe the brake apply and release on all the locomotive units as required by ConRail rules. (See appendix B.) After the locomotive units were coupled to the train, an initial terminal airbrake test was performed. En route, the engineer used the automatic brake several times, including a stop at Baltimore. The engineer later stated that the brakes did not respond

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Figure 2. Damaged lead locomotive unit of train WA-4.

properly to his service application at the Baltimore stop, and he had to put the brake valve handle into "handle off" position to stop the train.

The caboose of train WA-6 was provided with battery-operated flashing red marker lights with 4-inch lenses. One such marker was mounted on each side of the rear platform just under the roof level.

Once the airbrake system is fully charged, the brake pipe, auxiliary reservoir, and emergency reservoir are at equal pressures. A service application initiated by the engineer reduces pressure in the brake pipe by means of the locomotive brake valve which, in turn, causes the brake valve on each car to allow air pressure from the auxiliary reservoir to enter the brake cylinder on each car and apply the brakes.

In order to accelerate release of the train's brake after a service application, air pressure from the emergency reservoir (which remains fully charged during a service brake application) is used to provide partial recharging of the auxiliary reservoir. While this action quickens the release of the train's brakes, it also reduces the air pressure available for subsequent service and emergency brake applications until the entire system is again fully charged. Since fully recharging the brake system after a brake application requires considerable time, it is possible for an engineer to make repeated brake applications before the system pressure is fully restored. Thus, the frequent applications and releases of the brake can result in reduced braking effect in both the service and emergency modes if sufficient recharging time is not permitted. The time required to fully recharge the brake system is dependent on the amount of depletion of the system.

Crewmember Information

The engineer of train WA-4 was hired by the railroad as a fireman in 1969, and entered the carrier's engineer training school in October 1974. His actual service as a fireman totalled about 10 months which was interrupted by 4 years of military service. His formal training spanned 4 1/2 months and consisted of classroom instruction, on-the-job training, and qualification on the Philadelphia-Potomac Yard territory. Included in the classroom instruction were courses on the design and operation of the airbrake systems. During the on-job-training portion of the course, trainees were instructed in train handling and methods of operating the air brake system. The engineer reentered actual service about 1 year before the accident. During this time he had a physical examination and attended a class on the operating rules.

The front brakeman of train WA-4 was hired in 1972 and had a total of about 10 months service as a trainman before the accident.

The engineer of train WA-6 graduated from the engineer training school in November 1973, and worked as a qualified engineer until the time of the accident. The conductor of WA-6 had 8 years service as a trainman and was promoted about 1973. The flagman had worked as a brakeman on the territory involved since February 1977.

All of these employees had received physical examinations and had received periodic formal instructions on the operating rules. None of the crewmembers had been restricted for service.

Method of Operation

Trains are controlled over the four-track line by an automatic signal system, by cab signals, and by interlocking signals remotely controlled by the operator at Bay. The main tracks are numbered 1 through 4, from east to west. Tracks Nos. 1 and 2 are used as northbound and Nos. 3 and 4 as southbound. Wayside signals are of the position-light type with the tracks signalled in the designated directions. Tracks Nos. 2 and 4 are nominally assigned to passenger trains but are used by freight trains.

Maximum authorized speed for freight trains is 50 mph on track No. 2. Limited speed and medium speed are defined as not exceeding 45 and 30 mph, respectively.

The operator at Bay controls the northbound semi-automatic signals for track No. 2 at Bay, North Point, and River. The distances separating the three signals are 6,267 feet and 7,143 feet, respectively. Automatic signal 880 at Stemmers Run is located 8,647 feet north of River.

The operator can display a "proceed" aspect on any of the controlled semi-automatic signals by moving a lever on his control panel.

block beyond the signal is occupied by a train, the signal will display the following aspect:

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If the block governed by the signal is clear and the block in advance of that block is occupied, the signal will display the following aspect:

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If both blocks in advance of the signal are unoccupied, the signal

will display the following aspect.

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The semi-automatic signals do not automatically clear when a train leaves the block governed. The operator initiates the action by operating a signal lever.

Signal 880 at Stemmers Run is an automatic signal. If a train occupies the block governed by this signal, the signal will automatically display the following aspect:

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If the block governed by signal 880 is clear and the block in advance of that block is occupied, signal 880 will automatically display the following aspect:

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If both blocks in advance of signal 880 are clear, the signal will automatically display the following aspect:

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The cab signal displays an aspect to the engineer which informs him of the condition of the signal block in which he is operating.

When a train is stopped by an emergency application of the brakes, crewmembers are required to protect 1/ the adjacent tracks at the front and rear of the train until it is determined that the adjacent tracks are not fouled. (See rule 102, appendix A.)

1/ To protect the tracks, crewmembers must detrain with the proper signals and go a sufficient distance so that other approaching trains can be signalled to stop before colliding with the standing train as per rule 99, appendix A.

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