> How far back in history does this policy extend?

It's not a policy but a Law known as the Right of Way Banking Act, enacted by Congress in 1983. The big impetus for its passage was the scale of abandonments which resulted from the formation of Conrail in 1978, after the collapse of the PC in 1976, and the wholesale abandonment of numerous redundant RRs folded into Conrail. The realization dawned that once an abandoned line was gone, it would be virtually impossible to reconstitute it in a reasonably economical way at some date in the future should urban growth and population densities make it desirable, not to mention urgently so, for re-use in some form of rail transportation. In other words, the entire process of right of way re-acquisition, however accomplished, would be prohibitively expensive, not to mention a very arduous process.

> So, conceivably, everywhere where homes or other buildings have been built on abandoned railroad rights-of-way, if it was ever decided to re-install the railroad, those buildings would have to be torn down?

R/Ws in the railbanking program, which is administered by the STB, aren't abandoned. Think of them as being mothballed--the R/W, not the tracks, which usually get torn up and scrapped. Any building built on a former R/W (like those homes you mention) would have to own the piece of the former R/W where it sits, which means either R/W wasn't put in the bank, or the building predated 1983.

> There's an automobile assembly plant built on the abandoned NYC right-of-way between Cincinnati and Indianapolis. That would be interesting if it was ever decided to make that route a high speed bullet train route. Something tells me they would route the rail line around the factory.

The question here is: was that NYC line abandoned prior to enactment of the R/W banking act? If yes, then it could very likely be more or less "gone". Since no RR R/W is wide enough for such a plant, was the plant built on what had been a NYC switching yard?

> Once a ROW gets turned into a trail that ROW is gone forever for any railroad use.

Bzzzzt! It's Beulah the Buzzer. All that's necessary to turn it back into an RR is for a certified rail operator to file a certificate of need with the STB. If the Board approves, the trail is history, and the operator "gets" the R/W to use for trains, although it will have to buy any improvements made by the displaced custodian. Again, the whole purpose of the R/W bank is to preserve "old" rights of way should a need arise to use any of them again.

Several years ago, this almost came to pass with PLA in Niles Canyon. The UP and ACE were looking into relieving congestion on the section of the former WP line which runs mostly along the South side of Alameda Creek through the Niles Canyon between Niles and Sunol. PLA's track on the former SP R/W runs essentially parallel on the North side, and the intent was to make CTC 2MT between Sunol and Niles. Had this come to pass, the UP and/or the funding agency for ACE would have had to purchase PLA's track. Fortunately, this scheme fell through.

Also see FUD's post: "I know of at least one case where a railbanked r/w was reclaimed for rail use: [railroad.net] So don't say 'never' too strongly." There have been other cases, but I forget the details.