East of  Belen, New Mexico the Santa Fe and its successor the BNSF climb out of the Rio Grande Valley via  Abo Canyon.  This narrow and single tracked railroad bottleneck is a railfan's paradise.  The scenery is great, the trains usually frequent and the weather a whole lot better than Sherman Hill.  As of Fall 2003, there are no trespassing signs and gates at both ends of the canyon.  In the post 9-11 environment, access without permission is a bad idea.