Emergency brake (train)

The driver can press an override button and hold the brakes off whilst they choose a safe place to stop the train.

Because of possible serious problems, severe fines and/or imprisonment penalties are in place to deter people from activating the brake without good reason.

Despite the obvious safety hazards, sometimes this is resorted to by drivers when driving trains through sections where spurious ACP incidents are very common.

[4] The Regelung B009 NBÜ Rev 3.1 defines a set of nested state machines in the chapter “Anlage 1: Phasen einer Zugfahrt“, reflecting a very wide range of use cases, including platforms, tunnels, etc.

and is applicable for subways, trams, metros(S-Bahn), as it implements appropriate actions for all use cases occurring in rail transportation.

The implementation of the S-Bahn's emergency brake however does currently not reflect the state of the art in Germany,[8] it has failed in practical use at least in one instance 2015,[9] as a driver lost consciousness completely, but still accidentally triggered the vigilance device.

Without ATP enabled or over-speed, the described incident may have been leading to fatalities and substantial damage, as the passengers noticed the unconscious driver, but could not stop the train by pulling the emergency-brake-handle.

Using the NBÜ2004, as used in regional- and long-distance-trains, this would have been prevented, a "overwrite" response is needed, typically the "FÜ"(Filling) position of the automatic brake-lever, otherwise the trains brake-computer will perform an emergency-brake after 10 seconds.

[13] Illegal chain-pulling is a serious problem on Indian Railways; where miscreants do so to make unscheduled stops near their destination, which delays trains.

In an effort to improve the service, former President of India Dr. A. P. J. Abdul Kalam proposed an alternate method wherein a passenger in an emergency communicates with the guard and driver of the train.

This means a member of the train crew must locate the open valve, and ascertain that there is no problem which would make it unsafe to release the brakes and proceed.

In newer Amtrak equipment, the air-operated communicating system was electrified, and operated by pressing a button located in the vestibule.

At first, this means of communication was a cord running down the length of the train at roof level outside the carriages, connected to a bell on the locomotive.

Until the 1970s a "cord" (by that time a chain) was still used, which ran the length of the carriage and connected to a valve at one end which opened the brake pipe.

A butterfly valve on the side of the carriage was used to reset the brake, and also made it easy for the train crew to see in which coach the cord had been pulled.

[16] In most rolling stock built since the 1980s, passenger communication handles (or PassComms) have been installed, which activate an alarm in the driver's cab when used.

If the train is not in a safe place (in a tunnel or on a bridge, for example) the driver has approximately three seconds to override the alarm by pressing a button before the brakes automatically apply.

On some modern trains, the PassComm in a disabled-friendly toilet is mounted such that it is often confused with the door or flush control; this sometimes leads to accidental activation.

On older systems, marker boards showing an exclamation mark were provided on departure from each station at the point where the rear of the train would no longer be at the platform.

Turning the handle down (anti-clockwise) by about 90 degrees causes pneumatic brakes to engage, due to pressure loss in the standard air-braking system.

While primitive and not allowing any override such a system is effective, resembling usual train brake activation; it does not fail in emergency conditions.

It is dangerous to stop in a tunnel if a fire develops; an emergency exit could lead to electrocution by the third rail (typically energized with 825 volts DC).

In an emergency, there are door-control handles (visible to passengers) which are intended to make the pneumatic train doors able to be opened by removing air pressure.

In the US, the universally recognized signal to stop is a sweeping, horizontal hand motion, back-and-forth, at arm's length and perpendicular to the track (preferably in a downward direction, so as to distinguish it from a mere greeting).

Drivers are trained to interpret any urgent waving or signalling by a person near the track as a possible warning of danger, perhaps requiring an immediate stop, depending upon the particular circumstances present.