Editing Train stop (section)

==Types of train stops==
There are three types of train stops:
*Trip stop - stops train trying to pass red signal
*Timed train stop - stops train moving too fast
*Fixed train stop - prevents any trains from passing a point

===Trip stops===
<!--[[Image:ON-TTC 20071110 SubwaySignalling-TrippingArm Union.jpg|right|thumb|A raised trip arm]]-->
The trip arm is raised whenever the signal is not displaying a proceed aspect. If a train tries to pass the signal, the trip cock on the train strikes the raised trip arm and the train is brought to a halt. When the signal indicates it is safe to proceed ''(clear or caution)'', the trip arm is lowered, and a train is able to proceed without further hindrance. In some cases, the trip arm will not be lowered when the signal to which it applies is exhibiting a proceed indication, e.g. when subsidiary signals are cleared, forcing a train to trip before proceeding, thus ensuring that movements are conducted at safe speeds.

===Timed train stops===
With a timed train stop, the trip arm stays raised until the approaching train has {{Clarify|reason=I'm not sure if this is jargon or informal, but plain English should be preferred|date=February 2025|text=shunted}} a [[track circuit]] on the approach for a period of time corresponding to a set speed. If the train approaches at a speed higher than the one that is set, the trip arm remains raised and trips the train to a stop. If the train approaches at a speed equal to or lower than the set speed, the trip arm lowers before the train arrives, and the train is able to proceed without further hindrance.

Some timed train stops require the [[Railroad engineer|driver]] to acknowledge a stimulus before the trip arm is lowered on a yellow signal.

For sections of track with lower speed limits ({{Convert|15-20|km/h|4=0|abbr=on|disp=semicolon}}) a simpler construction is also used. The trip arm rotates freely on a horizontal axis with a counterbalance attached to its lower end. If a train's speed is low, the arm will be rotated by the trip cock with a force insufficient to initiate braking. But if its speed is too high, force will be large due to the counterbalance [[inertia]], causing the brakes to be applied.

=== Fixed train stops ===
With fixed train stops, the trip arm cannot be lowered. Fixed stops are positioned close to the end of a dead-end track, to stop a train before it runs out of track. They may also be used at the end of track sections beyond which certain trains should not pass, such as the end of electrified territory (e.g. [[Hamilton railway station, New South Wales|Hamilton, NSW]]), or to test the automatic brake and tripgear of trains departing certain locations, e.g. storage sidings, near buffer stops.

A fixed train stop that is the last one on a running line in the reverse direction may, despite its name, be suppressed, as is the case with the associated "Fixed Signals" on the Sydney network. Suppression is needed because in Sydney, the rear trip cock on a train is always lowered, while in [[Railways in Melbourne|Melbourne]], by contrast, suppression is not required because the trip cock at the rear of a train is always raised clear of any wayside trip arm.

Some railways and rail transit agencies use fixed train stops to protect workers in work zones by temporarily applying them at either end of the zone, preventing trains from incorrectly entering the work zone.