Whistle Stop at Lava Tank ©2017 James D Peterson. On the narrow gauge Cumbres and Toltec Scenic Railroad (formerly part of the Denver and Rio Grande Western Railway), engine 489 makes a whistle stop. This historic stretch of the old D&RGW line, between Antonito, Colorado and Chama, New Mexico, crosses the state line 11 times along its 64 mile route through the San Juan Mountains. This tank takes its name from the lava flows that form the plain upon which it is situated.