Points & Signals

[Ray H]

I'm pondering over the operation of the points and signals on the layout which I'm about to re-start (my initial attempt got as far as ballasted track before I realised the downsides of extra long cassettes, but that's another story).

 

With the exception of a crossover and the two associated shunt signals (which are on an adjacent board), all the signals and pointwork is on a single board. My original thinking was to use motors (probably Cobalts) to dirve each signal and turnout, operating them from a Gem lever frame, modified so that each lever operates a sub minature micro switch which will operate the motor as the switch is opened/closed. One of the motor's inbuilt switches would then be used to switch the common crossing (frog) polarity.

 

I then realised that I could just as easily use the micro switch to switch the polarity and use Mercontrol to work the point/signal saving me a few pence for each point and signal (about £280 in total).

 

Although the layout is DCC it is my intention to use a lever frame rather than DCC encoders to operate points and signals so I can't see that I need the second inbuilt switch on the motor.

 

Can anyone spot anything obvious that I might be overlooking before I ditch the idea of buying the motors and buy a few meters of tube and wire?

 

I would like to interlock the levers on what will be a 24 lever frame. Mechanical interlocking (on a suitable frame) is beyond my patience level so I was planning on electrical interlocking. However, I can't work out a way to physically stop the levers from being moved if the required other levers haven't been operated appropriately. The nearest I could get was to use LEDs adjacent to the levers which would either show green when a lever could be operated or red when it shouldn't be operated. Once again, am I missing the blindingly obvious and would I need to specifically use motorised points/signals for interlocking to function? I envisaged that I'd use the above mentioned micro switch to operate one or more relays that would provide the circuitry to set the interlocking indicators appropriately.

 

Apologies of this has been covered before.

[The Stationmaster]

I would like to interlock the levers on what will be a 24 lever frame. Mechanical interlocking (on a suitable frame) is beyond my patience level so I was planning on electrical interlocking. However, I can't work out a way to physically stop the levers from being moved if the required other levers haven't been operated appropriately. The nearest I could get was to use LEDs adjacent to the levers which would either show green when a lever could be operated or red when it shouldn't be operated. Once again, am I missing the blindingly obvious and would I need to specifically use motorised points/signals for interlocking to function? I envisaged that I'd use the above mentioned micro switch to operate one or more relays that would provide the circuitry to set the interlocking indicators appropriately.

 

Apologies of this has been covered before.

 

I think the only way to physically lock the levers when using electric interlocking on a mechanical frame is by means of a solenoid to 'lift' a mechanical lock - in other words the business end of the interlocking has to mechanically interact with the lever frame (probably best done by having a tappet off the lever I suggest). But that doesn't solve you problem does it? So the other - far simpler but in a way 'incorrect' - approach is to have locking which doesn't physically lock or backlock the levers - but that does mean you would need to electrically operate the functions worked by the levers, i.e. the points and signals unless you are going to be satisfied with just having the indicators you mention. (I did it using totally separate electric interlocking as I had electrically worked points & signals - but the levers on the GEM frames remained 'free'.)

I think the latter is a nice straightforward solution if it suits your needs and you are happy with it but you will still need to design your whole interlocking and don't overlook the backlocks - which are just as important as the locks and releases. If you're at Members' Day come and have a chat through your proposed Locking Table or how to draw one up if you're unfamiliar with the process.

[Blue Diamond]

I intend to do the same thing to my layout. Mechanical interlocking with DCC operation.

 

Have you considered Modratec interlocking, http://modratec.com/ or if you want true interlocking with signals, there is McKenzie in HO land, http://www.mckenzies.net.au/

[Grovenor]

If you want to save the considerable cost of point motors etc then mercontrol or other mechanical linkages are fine, I have two yards done that way with GEM frames but using model aircraft rodding rather than mercontrol.

However, if you want a properly interlocked frame you are going to spend all your saving and more unless you do a DIY type mechanical frame. Modratec supply the parts for mechanical locking at a significant cost and you still have to do quite a lot of the work. An alternative is to make electrical locking, servos are probably easier than solenoids to set up but again the cost is not inconsiderable, A frame recently done that way costed out at about £12 per lever.

Regards

Keith

[Ray H]

I like the two Australian offerings but I don't have either space or money for them - I've already spent too much on the railway!

 

If I go down the Mercontrol route I have to make that decision now and then decide exactly where the frame is going (and where all the signals will be located so that I can lay in the tubes before I ballast). Going down the motorised option, although more expensive, I can just buy what I need now (basically for the points) and temporarily lash up a remote switch panel until I've formalised the frame's position (which will depend on where I position some buildings). I can buy more motors when I have the signals built and ready to install.

 

I can spread the purchase of things over a greater time period and leave myself free to change my plans for a while yet.

 

It sounds like the interlocking will have to be limited to visual warnings if I attempt to incorrectly move a lever or, more likely, to provision of visual indications of which levers can legitimately be moved at any one time.