Rail Combinator Signals

[theDemolisher13]

Is there a mod out there that let's me connect a red or green line to rail tracks so I can send a signal down the line just so I can build a checker to make sure my automated bots fully build the line and not bits and pieces of it when they also have to deal with landfill?

[atomizer]

You could use the train pathfinder to check whether there is a continuous rail. Add a dummy branch on one side with a locomotive behind a force-closed signal. On the other end, add a station with a unique name, and add the station to the locomotive's schedule. Enable "read train count" on the station. When there is a continuous path, the station will read C=1.