Yeah...we'll regret that at some point, IMHO. They've converted all the railway right-of-ways around here into running/biking trails, which is in no way terrible. But at some point we're going to wish we still had those railways as very-low-carbon delivery networks.
They did a lot of the "rails to trails" stuff around here as well, but the underlying deal is that it's all technically land-banked and the railroads can claim it back at basically any time as long as it gets put to active use.
You still have to rebuild the infrastructure from scratch. So yes, we can piss off all the new users by reclaiming the right of ways (technically). But there's still a huge cost in recreating what was torn up to make it useful for a different purpose. My own opinion is that between the "piss off new users" and "cost of rebuilding", these right of ways will stay "rails to trails" forever. Which, again, isn't a bad thing.
There are a few reasons for the mass abandonment of railroad track. Probably the biggest (at least in the US) is railroad consolidation--we've gone from ~100 Class I railroads to 7 (8 if you include Ferromex in Mexico). This consolidation means you don't need parallel mainlines. Additionally, train traffic has generally shifted from serving individual cars to customers along the tracks to a heavier emphasis on delivering to consolidated freight stations (with last-mile delivery handled by local truck), which means the utility of tracks in the suburbs is lessened.
In 1936 the UK was already consolidated down to 4 companies (IIRC). The big abandonment was deliberate government policy in the 60s, and the logic was exactly last-mile truck (or bus) delivery with rail for the trunk. But it turned out that once you put things on a truck, they tended to stay there the whole way, since changing modes has significant friction and the country isn't vast.
Yeah, we can just...build back the stuff that was already there that we could have used for the cost of renovation but now have to rebuild from scratch. lolimsosmartarntI!
The absolute key is to still have the right of way. Bonus if the bridges are still sound. Putting the rails back is trivial and all the other infrastructure (signals, level crossings, safety fences etc) has to be renewed anyway.
In the case of disused (bike trail) rail corridors around here (Ottawa) I think the chief concern would be NIMBY pressure. Going from a quiet bike trail to a busy commuter train route... OMG property values!
> In the case of disused (bike trail) rail corridors around here (Ottawa) I think the chief concern would be NIMBY pressure. Going from a quiet bike trail to a busy commuter train route... OMG property values!
About a decade ago, CN bought out the EJ&E to use as a bypass around Chicago. The communities near the tracks were outraged and tried to block the deal, since it would transform the railway from a low-traffic route to a much higher-traffic. Yeah, there's serious NIMBY pressure on merely upgrading a train route; reconverting a local trail is going to be seriously worse.
But that's my opinion...I could be wrong.