axle counting is old hat... utilising gps is ( should have been ) the way to go.
GPS has been around for quite a while now - the first GPS satellite was launched in 1978. It was, and still is a US military system, although in the nineties it was officially designated as a dual-use system in 1996 by Bill Clinton.
Until 2000, civilian users of GPS only received a degraded form of GPS signal under a system called Selective Availability which resulted in much less accuracy (~100s of metres from memory). The stated intent of the US is not to re-implement SA again - but they can if they wish. One can think of scenarios including use in terrorist attacks or other armed conflicts which could prompt the US to turn SA back on - at least temporarily. Would you really want a level crossing system to suddenly think a train was much further away than it is?
This control of GPS by the US is why other countries and alliances have and are developing their own systems - eg the EU's Galileo, China's COMPASS, India's IRNSS and Russia's GLONASS.
[Other ways of enhancing GPS down to extreme accuracy even with SA do exist such as Differential GPS which existed long before SA was turned off. However it is suddenly not quite so simple.]
Trivia: SA was turned off during the first Gulf War for a time because the US military could not source sufficient military GPS models and instead had to purchase thousands of civilian units for their soldiers.