Does anyone know the name and/or manufacturer of these and what purpose they serve?
Trip-arm for the Trip-Cock on Metro Trains.
Trip-arm normally rises when the signal is indicating a danger aspect and if in contact of the trip-cock on the train passing the trip-arm, it will cause the train to stop in an emergency braking setting.
It's a safety measure.
That is a train stop.
A tripcock is located on the front of all leading bogies. If a driver passes a red signal the raised arm of the train stop will hit the tripcock and apply the breaks. You’ll find them mainly in the inner core. The yellow pod behind it is part of the track detection equipment.
Trip-Cock: Comeng (EDI,Alstom), Xtrapolis, Siemens and HCMT.
So which trains have tripcocks? I would be guessing the Comengs but what about the Siemens and Xtrapolis trains? I know that we also have TPWS grids which do the same thing but electromagnetically (for compatible trains)
I don't know if it's been fixed, but for a long time the down trip-cock at Huntingdale station was in an operating state yet was in a position/orientation where it could not interface with a train if it needed to.Now you've done it! You'd better hope nobody in authority reads this or poor Metro might actually have to do some maintenance.
This is a type of train stop attached to a signal that can display a low speed indication. The trip arm still works normally while the signal is at stop. However, when the signal is changed to low speed, the arm will stay up. As the train approaches the signal, sensors will measure the speed of the train, by counting how long it takes for the train to pass a certain section. If the speed is under 25km/h, the trip arm will drop and the train will be able to pass. However, if the train is over 25km/h, the train will strike the trip and be brought to a halt.
These trips are only found in major stations that have trains very close to each other. They are found along the length of a platform, seemingly not connected to any signal. However, they are connected to the signal at the end of the platform. When the signal at the end of the platform is at stop, all the trips will come up and act like a low speed trip. They will force the train to slow down for the red signal. The last trip, closest to the signal, requires a speed of about 4km/h.
Are these good descriptions?They're good enough. They're used in that manner to ensure the driver has the train under control at an appropriate speed so as not to SPAD at the signal, or if he does to minimize the distance he will travel past it.