Hi, Harold
I'm a big fan of the Logic-Rail Signal Animators. Their SAD-SBCA model is designed to drive the Tomar/Tortoise setup:
https://www.logicrailtech.com/xcart/product.php?productid=16226&cat=261&page=1
The signal animator used an IR emitter and collector. Some of the older photocell devices are still available, too. Once the train covers the IR the signal drops to red. After the end of the train clears, there is a selectable 10 or 20 second delay to yellow, then another delay to green.
http://www.logicrailtech.com/sad-sbca-ir.pdf
You can shunt the IR input so the signal is forced to red for a turnout or if you are running against the current of traffic.
For manual (train order) semaphores I have used the Hump Yard Purveyor switch lever.
Regards, Ed
How do you want the semaphore to function?
If it's just a turnout-position indicator, you can wire the Tortoise to the turnout driver if it's also a Tortoise.
There are simple occupancy detectors. I think Z-stuff makes one. The semaphore will operate when there's a train over the detector.
I have a couple of grade-crossing detection circuits I got from here:
http://home.cogeco.ca/~rpaisley4/CircuitIndex.html#Signals
These could also be used to operate a semaphore, although they're designed for crossing gates. Rob Paisley answers e-mails, and he might have a better suggestion.
It takes an iron man to play with a toy iron horse.
A servo motor, will work
oops mis read your question-
I have just purchased a Tomar Semaphore H-853, A Tortoise machine and a Circuitron 800-8100 Remote activator.
I would like to know if there is a way a way to activate the device with sensors IF or optic and not manualy?
Harold