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Re: HEP & refer containers & Electro-Pneumatic Braking
Author: Dr Zarkoff
Date: 09-12-2008 - 12:53
>The potential benefits of electro-pneumatic braking are indeed enormous.
Good idea. However, it was first considered in the Burlington tests of 1886 and discarded because of capital investment and maintenance costs. Resurrected c1905 for passenger service (certain services, not general, nation-wide use), it was given up on in the late 1960s for the same reasons. It was also almost given up on by the PCS (SF Peninsula) about 10 years ago for the same reasons. Now, the rrs are becoming disillusioned for it, under the guise of "micropocessor controlled", in general freight service [again] for precisely the same reasons. It's never been a sucess except for captive service, like Els and subways, certain passenger trains (like the Daylight, Broadway, 20th Century, commuter services like the MP-54s, and that ilk), and more recently unit [freight] trains where the cars so equipped never mix with "regular" fregiht cars.
There's also the concept of royalties to consider. The patents have expired on the AB and 26-C systems, so . . .
>I assume that with electro-pneumatic brakes, the trainline air pipe is kept fully charged at all times and the electrically controlled triple-valve applies the train brakes with air from the individual air reservoirs on each car.
The brake pipe pressure is reduced with each brake application, with the magnet valves on the cars admitting air to and from the brake cylinders. This is necessary in order to be prepared for what might happen next (like an emergency caused by a break in-two). It's a also a specficiation of the MCB/ARA/AAR since the 1886 Burlignton tests that each new brake system be backwards compatible with existing ones. This means ABDX/ABDLX will work just fine with HC/KC/AB (and for passenger, 26-C with PM/LN/UC/D22, and all of these with the freight systems). It has a tremendous number of refinements in the way of pressure sensitivity and response over these earlier systems, but the unlerlying principles and operation are the same.
Good idea. However, it was first considered in the Burlington tests of 1886 and discarded because of capital investment and maintenance costs. Resurrected c1905 for passenger service (certain services, not general, nation-wide use), it was given up on in the late 1960s for the same reasons. It was also almost given up on by the PCS (SF Peninsula) about 10 years ago for the same reasons. Now, the rrs are becoming disillusioned for it, under the guise of "micropocessor controlled", in general freight service [again] for precisely the same reasons. It's never been a sucess except for captive service, like Els and subways, certain passenger trains (like the Daylight, Broadway, 20th Century, commuter services like the MP-54s, and that ilk), and more recently unit [freight] trains where the cars so equipped never mix with "regular" fregiht cars.
There's also the concept of royalties to consider. The patents have expired on the AB and 26-C systems, so . . .
>I assume that with electro-pneumatic brakes, the trainline air pipe is kept fully charged at all times and the electrically controlled triple-valve applies the train brakes with air from the individual air reservoirs on each car.
The brake pipe pressure is reduced with each brake application, with the magnet valves on the cars admitting air to and from the brake cylinders. This is necessary in order to be prepared for what might happen next (like an emergency caused by a break in-two). It's a also a specficiation of the MCB/ARA/AAR since the 1886 Burlignton tests that each new brake system be backwards compatible with existing ones. This means ABDX/ABDLX will work just fine with HC/KC/AB (and for passenger, 26-C with PM/LN/UC/D22, and all of these with the freight systems). It has a tremendous number of refinements in the way of pressure sensitivity and response over these earlier systems, but the unlerlying principles and operation are the same.
