There's a few things that puzzle me. To understand the situation at the time, I'm trying to place myself in the early part of the 20th century when electricity was an innovation that was not widely available outside large towns, rather than the present day when its universal availability is taken for granted.
Where did the power for track circuits come from? In the case of St. Albans, was it from the local electricity power station, or from accumulators, and , if the latter, how were they recharged?
In the case of Quintinshill (which would perhaps not have been the highest priority for track circuiting without the foreknowledge of the disaster) probably many miles from the nearest power station how would power supply be arranged?
With electric (colour light) signals it's obviously easy to use track circuits to operate signals, but I can't visualise how, in 1915, the St Albans' track circuits could have prevented signals being cleared, only how they could provide a reminder to the signalman of the presence of a train if he looked at the indicator.
If track circuits only indicated to a signalmen that a line was occupied it would not prevent the signalman from nevertheless clearing signals to create a collision.
This prompted me to do a bit of digging in Peter Woodbridge's
A Chronology of UK Railway Signalling, with interesting results.
1835 - the electric relay invented by Davy in the UK and (separately) Henry in the USA
1837 - the Daniell cell (zinc-copper wet cell) was invented. It was the first practical battery, extensively used in the early development of the electric telegraph.
1854 - Tyer & Co propose a complete train movement control system including a treadle-operated train presence detector but it proves too complex and sophisticated so he went on to develop his train signallng telegraph
1859 - Gaston Plante invents the lead-acid rechargeable battery
1866/7 - the first practical dynamos (DC generators) invented separately by three inventors (Wheatstone, Siemens and Varley)
1866 - Leclanche invents the zinc/manganese dioxide (later zinc/carbon) dry cell
1872 - William Robinson invents the "Closed Track Circuit" in New York
1875 - Charles Spagnoletti conducts first experiments with power operated signals (on the Circle Line)
1879 - Edison (US) and Swan (UK) invent a practical incandescent lamp
1879 - First electric train demonstrated by Siemens in Berlin
1881 - First DC generating station coupled to a distribution system, in New York
1886 - First AC generating station coupled to a distribution system, in Pittsburgh
1889 - First electric point motor (Baltimore & Ohio)
1894 - First UK implementation of track circuits (in Gasworks Tunnel, Kings Cross) to indicate line occupied/clear to signaller
1901 - First UK implementation of track circuit block, using electropneumatic signals (by the LSWR at Andover Junction)
1902 - Taylor System of all-electric power signalling installed at Grand Central Station, New York - including approach locking. (The system was powered by a 100V battery which was charged by running a petrol-electric generator once per week)
1903 - Hall automatic semaphore signalling installed by the NER between Alne and Thirsk
1903 - AC track circuits adopted by the Metropolitan District Railway
1904 - First colour light signal in East Boston Tunnel, USA
It's pretty clear that by 1910 when the Hawes Junction accident happened, all the technologies were in place to support track circuits interlocked with the signalling. So the fact that it took such a long time to roll out afterwards is not because of technology issues.