As a railway brat, I miss long distance train travel like crazy.
It also has to do with punctuating the journey with many small stations and always being added halts.
a 36 hour journey from Chennay to NJP in a Sleeper.. This is India.)
When I was a kid and used to go on vacation with family, the late train was so good for me. It meant few extra vacation hours before schools and homework would start. I hope it would become the same again. BTW, only my lifestyle has changed. Train timings are still there where they were 15 yrs ago or maybe have become "more relaxing" :-)
Good that they mentioned why it is not exact real time ..."For security and regulatory reasons, the information published on RailRadar is delayed for 5 or more minutes."
In between such points, IR may know train's realtime location, but it is not made public.
It is mentioned on the site that there are 6000 monitoring stations. Which means that, on average, there is a monitoring station every 11 kms (66k Km/ 6000). Considering an average speed of 80kmph, the location shown on the app can at max be 8.25 minutes old.
Electric railways usually only supply actually used sections of the railway with power, so they have to know train positions, too.
I check this before I leave every morning. I live just north of the Muni Metro East yard, so I can tell when a nice empty train is about to go into service and run over to the station just in time to catch it.
(In theory you can enable every train and bus line at once, but after a certain point the page never loads)
https://developers.google.com/maps/terms section 10.2b(iii)
"you may use the Google Maps API(s) to track assets such as cars, buses or other vehicles, as long as your tracking application is made available to the public without charge. For example, you may offer a free, public Maps API Implementation that displays real-time public transit or other transportation status information.)"
Trains visualized (mostly Russian)
This uses their schedules not actual tracking, but trains tend to run on time now.
That dubious honour appears to belong to the US Dept. of Defense: