Interface - The Journal of Wheel/Rail Interaction

GIRDER RAIL

Testing Girder Rail on the MBTA
By Mark O'Hara • October 2007

The Massachusetts Bay Transportation Authority (MBTA) began as a collection of street railway companies in the 19th century. Teams of horses pulled “streetcars” through the streets of Boston, transporting groups of people more quickly and comfortably than they could ever travel by stagecoach. By today’s standards, the track system over which the streetcars rode was very primitive. At the very beginning, the rails were roughsawn sections of hardwood timber set in paving stones. The timbers wore very quickly and were subject to harsh environmental conditions that shortened their life even more.

As the technology of steelmaking evolved, wooden rails were replaced with sections of cast iron. The early rail sections loosely resembled the steel ingots from which today’s rails are made. They were generally squat, thick-webbed sections that were spiked longitudinally to wooden timbers or “sleepers” laid in the ground beneath the paving stones. Eventually, the sleepers, or crossties, came to be laid perpendicular to the rails and plates began to be used to support the rails on the ties. As the manner of attaching the rails to ties changed, so did the configuration of the rails.

One of the early challenges for street railway operators was to provide a space next to the rail for the flange portion of the wheel to occupy. Girder rail, which incorporated a running surface and flangeway in one section, was developed to help accomplish this. Paving stones could be placed against both sides of the rail making for easier installation and maintenance.

There were many different girder rail sections in use during the early days of street railway transportation. Owing to the large number of foundries in almost every major U.S. city in the 1800s, there were different rail sections in use in every street railway system. Over time, many of these local foundries died out and along with them the individual rail sections they produced.

The Boston Elevated Railway Company, which succeeded the West End Street Railway Company and ultimately would become the MBTA, began to use two new girder rail sections produced by the Bethlehem Steel Company. These sections were 128-pound girder rail and 149-pound girder guard. The two sections were nearly identical, except the girder guard section had a raised flangeway component for use in curved track. The purpose of the raised guard was to reduce rail wear by restraining the wheel flange as it moved laterally in curves and to help minimize the chance of derailment. These rail sections were very successful and were used by other street railway companies in Toronto, Philadelphia, San Francisco and elsewhere.

Streetcars, trolleys and light rail vehicles of the MBTA and its predecessors ran on the Bethlehem Steel girder rail sections for more than 50 years. Over the years, demand for girder rail by U.S. transit systems declined to the point that Bethlehem Steel stopped rolling it. The MBTA was able to purchase enough of the last remaining girder rail to meet its replacement needs for several years.

Girder Rail Availability
As time went on, the MBTA realized that its inventory of girder rail was finite and that a replacement rail section was needed. European rail sections were evaluated for their compatibility with MBTA light rail vehicles, ongoing availability and other factors.

The MBTA identified a European section, GGR-118, and selected it to replace the Bethlehem sections that had been in use for so many years. The most attractive feature of GGR-118 was that it had a raised guard component, which was thought to be a critical requirement at the time. The rail also was the same height and base width as 115 RE, which also was used throughout the MBTA system.

After a couple of years, however, the producer of GGR-118 stopped rolling the section. This left the MBTA in a precarious position. As a cost cutting measure, the organization had reduced inventory of replacement parts wherever possible. Consequently there was only enough stock of GGR-118 on hand for spot renewals, with no possibility of large changeouts or new installations.

These developments sent MBTA engineers “back to the drawing board” to investigate potential replacements for a discontinued girder rail section for the second time in 15 years. As no girder rail was being produced domestically, several European sections were evaluated. After much research the MBTA decided to use a girder rail section known as NP4aM. (Toronto Transit had recently begun to use NP4aM after consuming its supply of GGR-118.) Although the rail’s height and width dimensions were not ideal, the MBTA thought the resulting compromise issues could be overcome. The flangeway width of the NP4aM rail, however, was an issue for the MBTA.

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