Best option is to get it added on OpenHistoricalMaps (OHM).  I believe the best way to do it is to do it in JOSM.  I think there is a wiki page on how to do it.  I am not well-versed on OHM and have only moved one rail over on Staten Island, but I did that manually.

Start and end dates can also be added, adding even more control because the lifecycle can even be changed from "proposed" to "construction" to "active" to "disused" to "abandoned" then "razed" and finally removed all together.  The timeline can then be scrubbed and the status change can be viewed over time whoch is even cooler!