Moderation in all things. Which is to say, a little railroading now and then, thoughtfully applied, can be a constructive and useful thing. I would not use, or like to play, a constant diet of it, but that's not enough to brand it unclean, never to be touched.
Not that we've actually defined "railroading" clearly, mind you, but I expect my position stands, regardless.
These discussions seem to usually polarize into attempts to make blanket statements - Always or Never. My experience is that the game is most usually payed somewhere in between, with shades of grey and nuances, and thus Sometimes rears its ugly head, and makes a mess out of our attempts to make the analog world into digital, two-state systems.
But, really, let us look beyond the common part of the analogy - the rails, the lack of choice in how we get from A to B. Let us note how that choice is not the only thing of value in the Universe...
Consider that, if you drove from A to B, you'd probably take one of the common highways anyway. You *could* take a hugely variant route, but let us be honest - you probably won't. And those highways typically follow the same general paths as the railroads. So, being on the railroad probably isn't all that different than driving your car, in terms of route.
And, while you've lost the ability to choose the route, you *gain* the ability to enjoy the ride. The driver of a car is busy driving the car. The driver cannot spend much attention on the scenery, cannot read a book, or take a nap. Discussion is limited to only the few people that are in the same car. Meanwhile, on the train you can get up, stretch your legs and get a sandwich in the next car, strike up conversations with strangers, dance in the aisles a bit if the mood strikes you. The railroad frees you to pay more attention to your *local* events, without having to concern yourself with the action of travel!
So, if you know you're going to point B, and there's a railroad going there, it may well make sense to jump on the train. The train is only eliminated as a reasonable choice if you've chosen a destination that trains don't run.