Well, this might be nearer "making your own", but it is based on vectors present in OSM. See this tutorial:
Open Street Map Vector Data in TransDEM with JOSMThis is what I was referring to in my earlier post. It is rather involved and I haven't used this method much, but I do remember being very satisfied with the results. It requires another free software package called JOSM. It can be downloaded from the url in the above post.
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Edit: I just retried this process and it still works well with the latest version of JOSM (version '6891'). It wasn't as involved as I thought it was. It only took me 15 minutes to vector map the railways around Winslow Jct. NJ.
Note the round dotted lines indicating abandoned railway! JOSM and OSM vectored them too!
Here's the same route over the DEM of the area: