This question concerns the Westinghouse braking system. If I understand correctly this video, in an emergency braking (e.g. in case of failure in main air pressure line) the pressure in the main pressure line decrease rapidly (main pressure line vented to the atmosphere), triggering the brakes. Brake cylinders are then pressurized with no modulation in brake cylinder pressure.

Anti lock systems are important on slippery rail track, especially due to fallen leaves as explained in this article (fr) and this article (fr). If I understand correctly, anti-lock braking system works by modulating the pressure in braking system. In case of emergency braking, the anti lock system must modulate the pressure in the braking cylinder.

The modulation in braking system pressure needed for anti-lock system seems to not be compatible with the emergency brake feature of the Westinghouse air braking system.

Can anti-lock system be fitted on a Westinghouse air brake systems? If so, how does it works in case of failure in main pressure line?

  • $\begingroup$ I think that you answered all of your question. An anti-lock system requires a more complicated system that also needs to be powered. It may be possible on passenger trains, but freight trains do not have power to the cars. $\endgroup$
    – hazzey
    Nov 4, 2020 at 20:30
  • $\begingroup$ @hazzey I don't know how the pressure is modulated on anti-lock systems. There can be a way to modulate pressure inside brake cylinder whatever the pressure just after the triple valve. $\endgroup$
    – Manu H
    Nov 4, 2020 at 20:53


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