THE CENTIPEDES' PROGENY. The latest issue of Trains has reached the Shops, with lots of good railroad reading. The Locomotive News describes RailPower's entry into the road switcher market, the model RP20BD (as .pdf). (Quoting from page 20, the magazine is not available on line.)

RailPower determined it would be right in the middle of the 2,000 hp EMD GP38/GP38-2 market. Could RP build a replacement? [Executive Vice President Gary] Eelman believes the RP20BD, powered by three German Deutz engines rated at 670 horsepower apiece is the answer.

The people at RailPower have been doing their homework. (Hey, if this occurred to me, people who do this stuff for a living ought to have thought of it years ago!)

The advantage of the small gensets is that with modern control systems, the engines can be fired up or powered down as required, reducing the emissions compared to the standard single-engine driving one alternator. [Baldwin designer Max] Essl didn't have that technology at his disposal.

Here's the marketing advantage Mr Eelman sees.

"Ultimately the Class Is will replace the GP38s," he said. "It boils down to economics. The GP38 is probably the finest locomotive ever built for its time. And while it's well-loved, at the end of the day, it's still got a big 16-cylinder prime mover. When a GP38 is running in the 8th notch [full throttle and parallel shunt] it's efficient, but for anything else it's not."

The RP20BD has three engine-and-alternator skids mounted longitudinally, rather than the six or eight modules installed transversely in Mr Essl's patents. The concept appears to admit of further scaling up.