Articles

Why not just have 2 (or 3 or 4) electronically-controlled air valves inserted in the brake air line distributed thru the train? The signal can propagate both directions from the valves and you don't have to rework a million rail cars.

Assume there is one valve in the Locomotive. One more valve 2/3 of the way back in the train could reduce the propagation delay to 4 seconds from 12 seconds. 3 more valves plus the one in the locomotive could get the delay under 2 seconds.

This system would be less wonderful for duty where you are adding or dropping cars, but would work fine for long-haul unit trains where you don't have to keep moving valves around to optimum locations.

FWIW,
Keith

So what. Electric application of railway brakes anything new? Come on, it's a century old - has been used in New York 1909!
  http://www.railway-technical.com/ep-brakes.shtml
All modern European fast passenger stock has electro pneumatic brakes, a system still compatible with the old Westinghouse brake.
The only thing new is the test of electrical brake application in the U.S.A., on freight trains.
I should appreciate if authors would have looked up the facts before publishing, were not limited to a U.S.A. only view. The word "universal" does not end on the U.S. borders.

Thomas --

The only thing new about this is the application to the US freight system, but that is a highly non-trivial challenge. The US freight system is a very different bear from European fast passenger trains, and just because something also runs on rails does not mean that the equipment is compatible.

Applying new technology to a vast array of anonymous, highly standardized, and roughly used vehicles presents substantial regulatory, logistical, and technical challenges, some of which are outlined in the article. I'd suggest you examine the problem more closely before you dismiss it as uninteresting.

I agree with Thomas Schmid that the author did not do enough homework before presenting his article. Regrettably, the author failed to ask:

1. Since brakes are for safety, what provisions does the ECP brake system have for electronic failures - is there redundancy, and what would "fail-safe" mean for a train with ECP?

2. Is ECP braking designed to be backwards-compatible (i.e., capable of functioning when part of a train not equipped with ECP? Does applying air pressure set the brake, or release it, and is that the same as for conventional air brakes? Schmid says that the European system of electro pneumatic brakes (Thomas - are they just used on fast passenger trains, and if so, why?) is compatible with the conventional air brake system, so it would appear that converting a rail car to ECP braking wouldn't prevent its use on a non-ECP train.

Westinghouse's original system was used on passenger trains. Freight trains were not so equipped even after the 1886 50 car trials in Iowa. Only after the ICC was passed in 1887 was it possible to obtain data on trainmen's death rates. This finally forced the Railway Appliance Law of 1893 which the railroads mostly refused to implement. Finally, after the revised law in the early 1900s the railroads switched to air brakes for freight trains.