REINVENTING THE DOODLEBUG. Live from the Third Rail asks "How New is the DMU?" An article in the Miami Herald about a commuter rail demonstration project linking Johnstown and Pittsburgh provokes the question. The term "diesel multiple unit" is a British term for a self-propelled diesel rail car capable of running in multiple with other self-propelled diesel rail cars. The car to be demonstrated is a new offering from Colorado Rail Car. In North America, the Budd Rail Diesel Car is the most commonly-used first-generation example, although Amtrak and some northeastern commuter rail authorities invested in a second-generation version that made use of the Metroliner tooling called the SPV-2000 (for "Self Propelled Vehicle for the year 2000.)

To my knowledge, none of these vehicles are still running, although the Superintendent will welcome corrections from Connecticut readers, should any still be running there. A few Rail Diesel Cars continue to serve remote parts of Canada.

The news report expresses concern about the new diesel multiple unit car being able to handle the west slope of The Mountain on The Pennsylvania Railroad.
But can the DMU make the grade? Specifically, can it climb the 2-percent grade that trains must negotiate between Johnstown and Altoona?

The answer will come April 15 when a DMU will roll through the region as part of a multistate demonstration, which begins and ends in Miami.

Trains en route from Johnstown to Altoona must traverse the steep and rugged Cresson Mountain, said Bob Abraham of Monroeville, regional director of Keystone Association of Rail Passengers.
The Budd Rail Diesel Car was up to the challenge. In the late 1950s and early 1960s, the Baltimore and Ohio Railroad offered a train called Daylight Speedliner connecting Pittsburgh with Baltimore. The train used Budd Rail Diesel Cars, which were not capable of pulling unpowered coaches. The Colorado Rail Car product has some train-hauling capability.

The folks at Live from the Third Rail wonder whether or not shorter self-propelled trains offering a more frequent service are an improvement over longer locomotive-hauled (or pushed trains) running less frequently. The answer to that depends in part on track capacity. In Railway Blunders (the usual suspects don't have it in stock), author Adrian Vaughan argues that the shorter more frequent Virgin Voyager trains on more frequent headways are not practical on the stressed-to-capacity British metals.

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