Problem interlocking crossing loop

[roger]

I am working on signalling a crossing loop with an industrial lead off each end of the loop. The main and loop line are bi-directional lines. I also have included shunting signals to allow the railway modeller operating this crossing loop to shunt a train which will service the industries off the shunting leads. Assume the operator needs to run the loco around the train consist which is standing in the loop. A shunt signal is pulled to allow the loco to proceed across a crossover onto the main. A shunting signal is then pulled to allow the loco to revers and proceed along the main line section of the loop. My problem is that I can also set a mainline signal for a train to enter from the opposite direction resulting in a head on. In modelling terms, this will cause an electrical problem as I intend to use the interlocking to apply cab power to the blocks on the layout.
Is there a way I can interlock the signals to prevent this happening?
Roger

[roger]

Further to my previous query, I also find that I can set signals for departure simultaneously at each end of either the main or loop roads. Is there a way I can prevent this? This may not be a problem with the prototype but with the model, I can potentially connect two cabs to the same block with consequent short circuit problems.
Rgds
Roger

[Harold]

For the information of other readers, roger has contacted MODRATEC Help and provided a SigScribe4 file illustrating his interlocking issue.

Unfortunately, roger, what you are trying to do requires conditional interlocking which is not possible with the MODRATEC Lever Frame at its present stage of development. From the perspective of SigScribe4 (which, as a design tool must reflect what can be done with a MODRATEC Lever Frame), when defining a route, specifying points as "both N & R" works fine for dead-end sidings but not for bidirectional loops.

One solution is to include a separate signal (and lever) for each path required. However, you can combine the outputs from the two (or more) levers to operate a single "physical" signal arm. MODRATEC has a mechanical "OR" gate which can perform this function - more details on our web site shortly.

Depending on the exact situation, another possibility is to use the "Include Divert" function to exclude unsafe situations although this will usually result in some compromise in operational flexibility.

With respect to your second post, roger, I think the only solution here is some external "electrical logic" driven by the Auxiliary Switches on the Lever Frame to eliminate the undesirable possibility.

[RedFred]

With reference to the mechanical OR gate mentioned above, the MODRATEC range of WIT (wire-in-tube) control products is now available. The details are at http://MODRATEC.com/wit.php and these items can be purchased on-line in the MODRATEC Shop.

[roger]

Good news - the new facility (in Version 1.0.8 ) to allow signal interlocking has solved my problem in setting a departure signal simultaneously from both ends from the same loop track. Thanks!
Roger