Our booking engine at tickets.railforums.co.uk (powered by TrainSplit) helps support the running of the forum with every ticket purchase! Find out more and ask any questions/give us feedback in this thread!
Looking at the historical images on Google Earth, the tracks were not here in December 2003, were there in September 2008 and December 2009, but had disappeared by April 2014.
Maybe a local company using it for some sort of training? There was a thread a few years ago about an isolated length of track complete with trackside equipment, miles from any extant or abandoned railway. It turned out to have been purpose built by a company providing training courses for railway staff.
Googling "Hellaby railway training site" does bring up some current vacancies for the location, so I would guess that yes - this is the location of an engineering company and they were using it for training purposes.
Here you can see a class 378 passing the road near Mitre Bridge level crossing - as you head north you will see it pass you at roughly the same speed the Google car is going, presumably on an overground service having recently left Willy Junction, next stop Shepherd's Bush.