Operating sequences for trap point and turnout actuators

[47137]

On my layout, a steep branch line (single track) descends to join the main line (also single track) at a junction. I have installed a catch point on the branch to protect the main line in the event of a runaway:

 

 

I am imagining, the points and the catch point are worked from a power box some distance away i.e. by motors not mechanical rodding. Supposing the route is set for the main line, and is being switched to the branch - would it be correct for the points to move, followed by the catch point closing, or should both movements happen at the same time? I am using Tortoise motors so I think I have the luxury of being able to wire them up for either.

 

The branch is really quite short, so we might think of it as a siding rather than a branch line, in case this alters the answer.

 

- Richard.

 

 

[Gwiwer]

It would be quite normal for the two turnouts to be operated simultaneously in the manner of a crossover from a single lever which can be done if you rig the one motor to both.  Otherwise the main line point must be set for the branch before the trap (not catch) point can be released and set for a move.  Such things are normally fully interlocked with the main line block system even for very minor sidings in order to prevent mishaps.

[Edwin_m]

Yes the points would be interlocked and would move together.  In a power installation this would be done by having two actuators driven off the same circuit.  They might work at slightly different speeds but it wouldn't be possible to get detection, and hence to signal a train to pass by on the main line, until the point blades were fully set for the main line and the trap was also set to derail anything coming out of the siding. 

 

For trap points this setting is always referred to as "normal".  Rules require that they are kept normal at all times during normal operation except when they are reversed to allow a move in or out of the siding.  On a power scheme the points will either flash on the panel when reversed to remind the signaller to normalise them, or they will auto-normalise when the interlocking determines they are no longer required reversed (unless the signaller inhibits this with the point key switch). 

 

The same applies if instead of a trap there is a headshunt or some other track which also prevents trains getting out from a siding onto the main line. 

[47137]

Thank you both gentlemen.

 

I can wire the two motors to operate together at the same time, and if I decide to go for a software-based control panel I can think about flashing indicators too!

 

I've also changed the topic title to refer to a trap (not catch) point.

 

- Richard.