facing point locks & catch points

[george stein]

Writing from the USA, so can't wander out & look for myself.  So, assuming a straightforward single-line through station with a passing loop and a bay road & small goods yard. GWR / Big Four era.  Please confirm or correct following comments.  The facing point locks would be at each end of the main/passing loop.  Catch points would be at the bay road turnout and the entrance/exit to the goods yard spur - to keep wagons from rolling onto main or passing loop.  Question: while the facing point locks are obviously controlled from the signal cabin, would the catch points be similarly controlled or would they be open/close with an adjacent ground lever operated by a member of the yard crew?  Am I correct to assume that this arrangement would NOT be required (except for catch points) at a branch line terminal station?  That is, the loco escape does not need facing points locks.  Thanks for help.

[Gwiwer]

FPLs are required at all points on "running lines" where a train approaches from the single track end and runs onto one of the diverging routes, in other words in the facing direction.  "Running lines" include the main line, branch lines, loops and the entrance to sidings and yards though not within those areas.

 

"Catch points" are placed at entrance to a loop or at the bottom of a gradient to catch a train running away in the wrong direction.  They are usually sprung in the direction of the derail so don't require working from anywhere.  

 

"Trap points" which appear to be the same thing exist to trap stray movements in the right direction so at the exit from sidings, yards, loops and sometimes bay or dock platforms.  They are worked.  Mostly by a signalman though within yards the trap might be released from the signalbox but operated by ground frame under the control of the shunter.  Trap points which control access towards a running line are also associated with signals to control the movements which catch points are not.

[Edwin_m]

Trap points are normally (no doubt somebody will know of an exception) worked from the same lever as the corresponding points on the main line, whether this is in the signal box or a ground frame.  Hence if the points are reversed for the move to/from the sidings the trap points will also be reversed into the position where they do not derail.  With the lever in the normal position the points are set for main line running and to derail anything that comes out of the siding/yard.  As Gwiwir says these are also interlocked with any signals controlling entry or exit to the yard/siding so the signals cannot be cleared unless the points are appropriately set. 

 

"Trap point" is indeed the correct terminology and has been for many years but "catch point" was and still is often incorrectly used to refer to a trap point. 

 

Facing point locks are only required on points used in the facing direction by passenger-carrying trains, so the loop points on a passenger line would have them.  However if the loop tracks are uni-directional then points into sidings and yards would normally be trailing to passenger-carrying trains and only goods trains or empty passenger trains would use them in the facing direction.  If this is so then the FPL is not needed. 

[beast66606]

Adding.

 

Trap points are generally only provided when non-passenger traffic uses the line, so a passenger bay would not always/often be trapped but a parcels bay would be.

Being a terminus makes no odds, the rules are still applied (mostly!)

[Grovenor]

"Catch points" are placed at entrance to a loop or at the bottom of a gradient to catch a train running away in the wrong direction.  They are usually sprung in the direction of the derail so don't require working from anywhere. 

Note, sprung catch points as described here cannot be used on a single line as they would be facing for half of the trains. Where considered essential because of the gradients catch points on a single line had to have provision for locking for the facing moves. Simple spring catch points are only applicable to double track as all normal traffic must trail through.

Keith

[The Stationmaster]

Note, sprung catch points as described here cannot be used on a single line as they would be facing for half of the trains. Where considered essential because of the gradients catch points on a single line had to have provision for locking for the facing moves. Simple spring catch points are only applicable to double track as all normal traffic must trail through.

Keith

Runaway catch points on single lines usually tended to be of the spring slotted variety.  The normal setting of the switches was towards the derail position and a movement trailing through them would work them on a spring in the usual fashion of a double line catch point - it was arranged this way so there was no chance of a sudden breakaway not being caught either because it occurred as the train was passing over the points or because a Signalman forgot to move them to open after a train had passed.

 

For movements in the facing direction the Signalman pulled the slot lever which pulled the switches up and then, as Grovenor said, operated the Facing Point Lock (FPL) to bolt the switches in the correct position.

 

The GWR also used spring slotted trap points in situations where you might not necessarily expect to find a trap point and they had certain interlocking advantages as well as offering their normal trapping protection; other Companies might have done the same but I only know of GWR examples. (And just to be awkward my current 'design thinking' for my intended layout will incorporate just such a trap but somehow I don't think it will work as a spring slot ).

 

Trap points could be provided on passenger bay lines 'if circumstances warranted their provision' - for example it might be a short bay where any inadvertent movement would fould the through line or it might be a bay where odd vehicles were regularly stabled - provision depended entirely on local circumstances and varied over the years..