What about the use of the "radio token" system used on some routes in Scotland (can't remember the proper name of the system)
Radio Electronic Token Block (RETB). Today that system needs all the paraphernalia of TPWS with indicators, motor points with indicators etc. Originally they used hydropneumatic train operated points but those are now obsolete and have all been replaced.
The quantity of equipment required for conventional TCB colour light signalling on single track branches has decreased significantly in recent years with the latest techniques. A good example of this is the axle counter replacing lots of individual track circuits through a long single line section. Each track circuit is limited typically to about 1km maximum length (they simply will not work reliably or safely over a longer distance), so for a 10km single line block section you'd need around 10 individual track circuits distributed evenly along the track, each with feed equipment and relays housed in lineside cabinets with power supplies and repeater circuits. All this equipment has to be maintained and periodically tested and adjusted. By contrast the same railway using axle counters would require only one low maintenance counting head sensor fitted to the rail at either extremity with no intermediate equipment whatsoever between, save for data link cables connecting each sensor to an evaluator unit situated at one end or the other.