Catch point

[mal1965]

Hi All.... Could some tell me where i would use catch points on a layout, as i'm new to N gauge and didnt use these on my 00 gauge so need a bit of advice on these products

[Leo1961]

There is a good explanation here http://en.wikipedia.org/wiki/Catch_points

But basically they are used to prevent any runaway wagons, coaches etc from causing any damage to other rolling stock 

[Skyline2uk]

I would be interested in a response on this subject from the many knowledgeable people on the forum, but my limited understanding of these is that they are used to protect the mainline from stray stock (i.e. run away stock or just stock that has passed a red signal) by de-railing it before it could do any harm.

Classic places (and I stand by to be corrected) were I would expect to see a catch point would be at the exit of a depot or set of sidings as they join the main running lines. Of course the other way to protect from stray stock going onto the main line is to use a head shunt (i.e. a siding that has to be reversed out of to access the main line), but this is not always possible due to space limitations.

Hope that's good for a starter for ten?

Skyline2uk

[EtchedPixels]

If you are modelling modern image there are a lot less of them in favour of actual points, sand drags and buffers etc. I assume is cheaper and faster to clean up the mess.

[47033]

Catch points were strateglically placed near the bottom or part way up inclines years ago. They have been done away with in modern times as the requirement for them no longer exists.  Back in the days when partially or non fitted trains ran with Brake vans at the rear,  they would derail a train that may have broken apart (split) going up an incline. There would be a strong possibility that the brake van would be incapable of holding the weight and would run away back down the hill.  Hence the word catch point.
As all trains today are fully braked throughout they are no longer required.

A similar type of point exists today and is usually seen at the exit end of a loop or siding. In the event a train should pass a red signal and try to occupy a mainline without authority it would be derailed prior to doing so. These are refered to as Trap points (trap the train in the loop or siding etc) or split rail derail.

Jamie

[edwin_m]

Jamie and Wikipedia have it right on the distinction between catch points and trap points, something which "catches" out (or "traps") a surprising number of people. 

[47033]

Further to my explanation above and just to clarify. Catch points are trailing points and are spring loaded. When the train passes over them (in the normal direction) they close and re-open as each wheel hits them. Should single line working be needed and trains need to run in the wrong direction over the catch points, the Pilotman will use clamps to clip the catch points shut. A green handlamp will be placed at the point indicating to traincrew and the pilotman that the catch point is clamped shut and is safe for the train to pass over.

There were no speed restrictions passing over them in the normal (trailing)direction although when running wrong road over them (facing) it was a maximum of 15 mph. It may have been 10 mph but I think it was 15 mph, it was a long time ago now.

The eventual demise of 47131 at Dorrington between Church Stretton and Shrewsbury was because of catch points not clamped shut during single line working. The train went through them in the wrong direction when they were open and subsequently derailed.

Jamie