Earlier this week, Eurobricks user Xrisl made a great post about running LEGO trains in a prototypical manner using signalling and telegraph messaging. If you haven't already read it, it's well worth checking out.
The layout described uses 4.5v trains, track and signals. While the signals are used to control the trains, a separate telegraph system has been set up, allowing operators to send messaging to each other about the status of trains that are coming down the line. The layout is set up in a manner that allows operators to only see portions of the track, so, just like in real life, they need to rely on the messaging and signals to keep track of traffic.
Prototypical operation of trains is pretty common in the model railroading hobby, but isn't often done in L-gauge. The post by Xrisl is a wonderful example of what is possible when someone thinks outside of the oval, and looks to the real world for inspiration.