Is it more a representation that people in Southern land:
1) Are naturally more Conservative voters in the first place (so would be unlikely to sway en masse). Lots of the seats down there are very safe Conservative seats, and you'd need something catastrophic to swing them. The railways will rarely if ever provide something as big as that.
2) See the Unions as the problem rather than the politicians, therefore backing Corbyn's Labour party would be an unnatural progression to their minds?
I wouldn't dismiss the railways as being very low down on the agenda of people - the Southern commuter brigade have really been hit hard and it's certainly not a low priority for quite a lot of people down there who really have put up with quite significant disruption to their daily lives as a result of the dispute. For quite a lot of people, it's probably having a bigger immediate impact on them than our decision to leave the EU, for example.
And as for not having an effect - well Brighton Pavillion swung considerably towards the Greens who support renationalisation of the railways, and quickly surveying a handful of other seats in the area there was a strong boost for the Labour party throughout their network. Of course, this isn't out of kilter with the rest of England, but it's possible that the railways could have had some effect here. As I said, it takes more than trains to swing constituencies like these away from Conservative, but there has possibly been some effect. A lot of the safe seats are less safe now.