Train braking

[Anonymous]

Hello All ;
I've recentlly recieved a copy of 'Dream Trains', and just got to confirm the fact that some Streamliners used the so called EP, or electropneumatic brake, wich is, no more, no less than an electrical system used to acivate cars air brakes simultaneousely providing a faster recation of the and reding braking distances. Since that in my country such a system is used in Intercity trains running at 100 mph (with EP out of service they get to be limited at 87), was that a condition used also to reach high speeds ?
And nowadays, are there any railroads using it ?
Many thanks
Mario

[Anonymous]

If I am correct, we (BNSF) have some of the same style set-ups on some of our engines (mostly MACS). They are no longer in use and were used on some unit coal trains (as far as I know). I believe that they were manufactured by Knorr.

[Anonymous]

right i liked that book to

[Anonymous]

Correcting myself, I meant to say that the control boxes are mounted on some of our MACs for use on some electronically/pneumatically controlled brake valves found on some unit coal trains. As far as I know, they are no longer used.

[CSSHEGEWISCH]

Electropneumatic braking is used on LIRR M-1 cars and may be used on other MU's in suburban service.

[oltmannd]

EP braking is exactly as you describe. It was needed to speed up the brake application to get shorter braking distances needed for higher speed operation with existing signal spacing. Two things happened. One, the brake valves themselves improved so that the pnuematic braking signal speed increased to a point that the braking distance advantage of having the elecrical signal was very small. Second, it was difficult to maintain the electrical connectors between the passenger cars. Consequently, most EP braking systems were removed. Amtrak's Amfleet cars were delivered with EP, but it was removed, and the cars sucessfully operated in 125 MPH Metroliner service for years.

More recently, ECP braking has been developed for freight trains. In this instance, the entire brake valve is electronic, so not only is the braking signal sped up, but the time delay in actually applying air to the brake cylinders is reduced as well. Since freight trains are much longer than passenger trains, the benefit of ECP braking is fairly large. There have been some long term tests of ECP braking, but the electical connector issue still heads the list of trouble.

-Don