A sticking brake caused a stop in Kingston Swamp, Rhode Island. An inspection was made, and the angle cock that controlled the air brake connection between the third and fourth car was found in the closed position. This condition prevented the cars to the rear of the third car from having the brake released from the locomotive. The angle cock was opened, and train #173 proceeded 56 minutes behind schedule.
The train arrived in New Haven and the diesel was changed for a New Haven Railroad electric locomotive. Three cars were added and the crew changed. With no mention of the earlier brake problem, the 16-car train left for New York 45 minutes late.
The brakes operated correctly several times between New Haven and New York City, and the train arrived at Pennsylvania Station 38 minutes late. In New York, the New Haven Railroad electric locomotive was changed, and train #173 left New York with GG1 number 4876 in the lead and engineer Harry Brower at the controls.
"The Federal Express" made stops at Philadelphia, Wilmington and arrived in Baltimore 35 minutes late. The brakes were applied 14 times between New York and Baltimore without a problem.
The fourth car was destined for Baltimore and was set off and the train re- coupled. Leaving Baltimore, engineer Brower set the controls for 80 mph and did not apply the brakes until the train reached signal #1339, two miles from Washington's Union Station. Applying the brakes did not slow the train, so engineer Brower set the emergency brake, which should have brought the train to an immediate halt, but it did not stop.
Train #173 was running out of control on the downgrade of track 16 which dead- ended at the terminal. Brower knew that the brakes on the locomotive and the first few cars had applied, but the rest of the cars were pushing the train right into the station. He stayed at the controls and repeatedly blew the GG1's horn, warning everyone away from the track.
The operator in the tower at the entrance to Union Station heard the horn blasts and realized what they meant and called the stationmaster and told him that a runaway was coming on track 16 and to get out of the way. The station concourse was cleared quickly.
The train crashed through the wall, smashed through the stationmaster's office, which was just beyond the end of track 16, demolished the main news stand and was sliding across the concourse toward the waiting room when the floor gave way and the GG1 and two of the cars fell through the floor into the basement baggage room. The time of the wreck was set at 8:38 AM, 18 minutes later than the scheduled arrival for the "Federal Express", by the broken clock that was in the debris.
The cause of the wreck was found not to have been the same problem with the angle cock that had closed in Rhode Island, but a closed angle cock on the fourth car that had been the fifth car in Rhode Island. When the car was set off in Baltimore and the train re-coupled, the car inspector failed to open the angle cock on the now fourth car.
With the inauguration just days away and with thousands of visitors scheduled to arrive, the station had to be repaired quickly. By 7:00 AM the next day, the cars, which had fallen through the floor, had been removed. The GG1 was left in the baggage room, a temporary floor was built over the locomotive, and the station was opened just three days after the accident.
After the inauguration, the GG1 was cut into three pieces and removed from the station and sent to the Altoona Shops of the PRR. It was rebuilt, painted Tuscan red and returned to service. Number 4876 was among the very last GG1s in service.