Following up to my own post, (that wiki continues as "early alpha"), two important tasks emerge:
1) Denver RTD's University of Colorado A Line (train) needs nodes/ways added to OSM, tagged public_transport=platform to grow the route from public_transport:version=1 to v2. Seeing this is a pretty heavily-travelled passenger=suburban route=train, this shouldn't be too difficult, and
2) TIGER Review of existing mainline freight rail (primarily mainline BNSF routes Colorado Springs, Pikes Peak, Spanish Peaks and Walsenburg Subdivisions) will need some additional authoritative data sources (Colorado PUC?) to "untangle" them from UP lines: they have blurred so much and are have gotten so confused that the original TIGER data are virtually incomprehensible as they exist in OSM at present.
Of course, keeping the wiki synced with the data in OSM is the whole point. Then we go beta and eventually Colorado/Railroads become "a pretty darn good set of statewide rail data, well-documented." One state at a time, OSM rail data (from decade-old hoary TIGER data) do measurably and demonstrably improve.
Thanks, especially to Colorado OSMers/rail enthusiasts who have responded so far,
Thank you, Jay! That's a very rich website, I'm now fumbling my way through it and I think I can find the "platform/stop" locations I'm looking for, but it may take some data massaging to get those into OSM in a straight line. I find it kind of neat (circular logic?) that OSM is at least partly used as a basemap layer on this site's geo browser, although as I drill down to the data I'm looking for, the US DOT web site "becomes" a US DOT-branded site in the opendata.arcgis.com domain. OK, whatever; ArcGIS' open data portal using OSM doesn't surprise me, and they do properly attribute OSM.
Some of these data appear to be a national agglomeration of transit-authority-produced GTFS feeds, which is/was another method by which I might have obtained these data (they are published either by the transit authorities themselves or by similar, non-governmental, often academic sites which collate the data). I'm sort of slapping my forehead that I didn't think of GTFS data first, as I mentioned GTFS in a 2014 SOTM-US talk I gave on national bicycle routing; GTFS are really useful data, and them finding their way into OSM is a fairly natural thing to happen (given time, and here we are).
I'm also appreciative that the bts.gov data are quite fresh; it looks like they started the project in 2016 and some of the data are dated February, 2018. Great!
> When I worked at BNSF, that is what was used to initially populate the linework for our rail feature class.
I would have thought BNSF (and other Class I carriers) had their own maps of their own rail lines. Interesting that they use a .gov site (and data) to "populate the linework." Again, seems sort of circular, as the rail line data had to originate from somewhere.
> Class I railroads (the very large ones) are generally regulated by the Federal Railroad Administration. PUC is for telecom, electric and gas.
I had great luck with California's PUC and rail data: one was a statewide "crossing spreadsheet" that listed road/rail crossings and allowed OSM (me, in this case) to replace (at least in California) our rough TIGER rail data with proper Subdivision names. That took me some time to curate, but our California/Railroads wiki and useful products like OpenRailwayMap and OpenPublicTransportMap are all the better for it wherever OSM volunteers do this work. The California PUC also publishes an excellent PDF/hypertext of passenger rail data (a link to it is in our wiki) right down to the level of speed limits on segments and signal/switch names. That's pretty ambitious (especially in a state with as much rail as California) and I haven't incorporated those data into OSM, but the links are there for anybody who wants to bite that off and chew (and chew, and chew).
Part of what I'm doing is "building community" by launching Colorado/Railroads (as another statewide wiki "seed" for good rail documentation) in the hopes of inspiring others to do the same in their states. (We're up to ten or eleven states now with alpha/beta-level rail wiki pages). And, I was hoping that OSM volunteers would take heed to "Map Your Train Ride!" to get more platform/stop data into OSM's passenger train routes. But, there is more than one way to do all of these things, of course.
Fantastic there are so much good data "out there" and that we have people reading this list who know where to find them!