First off, in a different post I used the traffic light analogy when describing a railroad signaling system. That’s partially right. For a much better and in depth description of railroad signaling, and different types of railroad signal, check this out.
As it stands right now, none of the current AVR line mentioned in this proposal is signaled. Signals were removed from this route back in the PRR days. This means not only that all the signals and associated relay equipment will have to be re-installed, but any other remotely controlled switches/derails*/automatic stops** etc. and their associated relay equipment would have to be installed. This is a normal cost associated with setting up a commuter operation.
Additionally, special signaling would have to be supplied for the portion that runs at-grade on
26th street and on the Busway.
Here’s the good news. A local business getting the business. Union Switch and Signal (a part of Ansaldo) has their headquarters in the city. This sounds like a match made in heaven to me.
The signaling concept is pretty easy and straightforward. A light rail operation can use similar rules and signaling with a few modifications (mainly derails and Automatic train control devices). Aside from cost, there is little that would be more challenging than a heavy commuter line, or any other light rail for that matter.
*Apparently derails are required at controlled points where a heavy rail operation interlocks with a light rail operation. These devices will prevent an improperly directed train from entering prohibited territory.
** Automatic train control devices would be required at all interlockings. If a train does not have permission to proceed through the interlocking (by the signal protecting the interlocking), then an automatic train control device would kick in and stop the train. These devices require both rail vehicle modification and additional lineside equipment.