Railfans may care that an old RDG signal is still standing... the people who pay for the system do not. If you wish to sponsor SEPTA to maintain a relic when the rest of the world is moving on to new technology, go for it... I will go on applauding any new embracing of technology that SEPTA dares implement.
Hate to break it to you (and others who've made similar arguments in other threads), but SEPTA doesn't exist to maintain the old systems for railfans' pleasure. It exists to move people (note this) *today*.
SEPTA should exist to incorporate some cost effectiveness into its operations. I seriously doubt that the capital cost of a new system would ever be made up in "savings" (if any) from the replacement of the old.
BTW, all new signal upgrades on SEPTA are going to be cab signalled without waysides except for interlockings and CP points.
I know they installed some Rule 562 running on the R3 between JENKIN and NESH, but I am not even sure that that is good for bi-directional running. Not only will they still have to get Form D's for reverse movements, but when the CSS fails they'll need to do absolute block. SEPTA didn't even install 'C' lamps at JENKIN or NESH so forget about a Rule 281a aspect.
You're no longer dependent on being able to actually see the signal bridge, you're just given your signal directly (so software upgrades at a central location can improve how well trains are coordinated)?
There is great advantage for retaining the wayside signals, most notably when the CSS equipment on the trains fail. Second, HA! While SEPTA has closed the towers and remoted control the 1234 Market there is nothing like the "intelligent design" you suggest. All that has happened is that the dispatchers have become overloaded and SEPTA's ontime performance has plumeted (remember how they had to cancel the On Time or On us promotion?)
The R5 Main Line to Lansdale will not see 70 mph unless:
1) All new catanary is installed on both tracks.
2) All curves are all super-elevated.
3) All crossing protection is retimed to 70 Mph.
and guess what........there are no plans to do or pay for any of this work.
See what I mean? There will be no faster service. Just wasted effort.