train detector circuit

[cwclark]

I was surfing through the internet and found plans for a train detector circuit at gatewaynmra.org...Has anyone ever built this particular circuit and does it work?...I also need to know how to wire one of the inputs to a tortoise under the table switch machine to turn the bi-colored leds red at the search light target in case the turnout happens to be throw the wrong way against an oncoming train.