EXACTLY!!!!!
Not hard, is it?
What will have happened is that Network Rail or whoever will have specified what they wanted the programming of the machine to do, and put the job out to tender. They will then have contracted the cheapest contractor to do the job. A software specialist wrote the code to make it do exactly what was specified - and nothing more. There will have been the option to do extra work at punitive costs - because that's the only way contractors make any money on these sort of deals (I know - sometimes I'm one).
By the time someone realised some extra code to do what Arch suggested would be a good idea, the money to actually get the original contractor back to add it in would have been long gone. So now we're stuck with the system that's there.
Many of the half-baked systems and buildings I work with were built this way!
And why is it so massively expensive to go by train. Me and the wife needed to go to York a little while ago, we thought about going by train, £152 return and that didn't include the 50 mile car journey to and from the station + a couple of taxi journeys in york. So we went by car £33 for diesel. And the car journey was probably quicker!
Be fair: if you add in the cost of buying, owning, taxing, insuring and maintaining the car, it's probably a bit more than that. But still probably not £152.
Anyone remember that story about a party of journos who bought, taxed and insured a car, filled it with fuel and drove it from London to a conference in Newcastle (?) for less than the cost of the train fare?