CHAOS Report #5 - Clearances, A Matter of Inches - November 29, 2010

Mechanical Liaison Officer's report by Paul L. DeVerter II

Submitted by Jack Deasy.

Clearance profiles exist to protect railroad equipment from striking infrastructure, damaging both the equipment and the infrastructure, and potentially injuring crew, passengers and others in the vicinity of the incident.

Amtrak has four clearance profiles (A, B, C and D). Clearance profile “A”, which applies to the Pennsylvania Station complex (the station itself, the Hudson River and East River tunnels and Sunnyside Yard) in New York City, is the most restrictive profile. A car that meets clearance profile “A” can operate anywhere on the Amtrak national system.

Amtrak requires car owners to measure their cars, complete their PC-5 form and submit it to Amtrak. Any modifications to the car, completed over time, must be evaluated for their impact on (and possible change to) the car’s clearance profile.

Here are a few anecdotes of past situations pertaining to private cars and clearances.

Back in the late 1980s or early 1990s, the owners of a modernized heavyweight business car installed a new diesel generator system underneath their car, to replace a large diesel generator system that occupied valuable space inside the body of their car. Apparently the measurements of the clearance envelope occupied by the newly installed diesel generator system were not completely accurate, as a part of the diesel generator system touched the DC traction third rail when the car was passing thru the Pennsylvania Station complex. The display of electrical fireworks resulting from the electric arc between the car and the DC traction third rail was reported to be impressive. Fortunately, no one was injured.

A number of years ago, the owner of a heavyweight business car was visiting New York. A pair of classic marker lights was mounted in the car’s brackets. Unfortunately, they protruded far enough from the side wall of the car to strike the infrastructure; they did not survive the trip thru the tunnel. Fortunately, no one was injured.

In the mid 1990s, some friends of mine acquired a heavyweight business car that had been given a streamlined appearance by the installation of stainless steel fluting and trim over the car's existing body. Clearance measurements documented the fact that the car was a bit too wide to operate into Pennsylvania Station in New York. The good news is that the new owners were aware of this operating limitation before they purchased the car, thus avoiding a potential rude surprise at a later date.

Lovett Smith of New York Central 3 recently told the story of a clearance problem dating to the early days of his ownership of the car. “Larry Haines rode NYC 3 with us for about 15 minutes on its maiden voyage. Although his trip was only between New York and Newark, it was quite memorable -- we had a 5 inch "pigtail" phone antenna on the roof that exceeded the Northeast Corridor height requirements. It hit the overhead catenary, caused a huge arc that burned a hole in our roof, and it shorted the entire Hudson River tunnel. It was eerie, watching lights go out on other trains we had seen alongside us through the openings in the tunnel and to feel all of us gliding to a stop in the darkness.” This incident involved some damage to the car and an adverse impact on other Amtrak and New Jersey Transit trains in the area, but it was fortunate that no one was injured.

If your car will be traveling somewhere off the Amtrak system, to/thru a location where you think there may be a clearance concern, then it is strongly suggested you check with the Clearance Engineer of the host railroad. In January 2005, private cars Alexander Hamilton, Kitchi Gammi Club and Mount Vernon participated in a charter special train on Metro North Railroad, from Grand Central Terminal up the Hudson Line to Poughkeepsie and return to GCT. Metro North personnel traveled to New Jersey to inspect all three cars a few weeks before the trip, using “Go / No-Go” clearance gauges. The inspection found that Mount Vernon’s diesel fuel tank did not meet Metro North clearance, which is more restrictive than Amtrak’s “A” clearance. As a result, the fuel tank was raised several inches closer to the floor of the car, so that it satisfied the Metro North clearance profile. That relatively small adjustment probably avoided the car striking a dwarf signal, the 3rd rail or another object somewhere in Grand Central Terminal, the Park Avenue tunnel or other location during the special train operation.

We rarely see dome cars operating any distance under live catenary, but it has been done before. If your PC-5 clearance diagram documents your car's height above the rail and other dimensions will allow it to safely operate under the catenary, then Amtrak will consider your movement request. Several years ago, Luis Caceres, the former owner of dome-sleeper-lounge Moonlight Dome, successfully operated his car, with it's slightly lower profile dome, underneath energized catenary from Harrisburg to Philadelphia on the Three Rivers and then onward from Philadelphia to Washington on the Carolinian. Although the car did not meet the Amtrak “A” clearance requirement, Amtrak's Clearance Engineer reviewed the car's PC-5 clearance diagram and authorized movement of the occupied dome car under the wire on the Keystone Corridor and the southern part of the Northeast Corridor. Luis mentioned the carmen in 30th Street Station appeared astonished when the dome car arrived in Philadelphia on the The Three Rivers. The trip was completed without any clearance incidents.

The bottom line is that clearances all come down to a matter of inches. An inch too far in one direction and you have a problem; an inch less and all will be fine. Any modifications to your car must be designed to meet the most restrictive clearance in the territory where you want to operate your car. After the work is done, you have to carefully measure the car, document the measurements on Amtrak’s PC-5 form, and ensure it meets the desired clearance profile.

Jack Deasy