Jessica:
I have a D&RGW AFE on the new snow sheds and some documentation in D&RGW files and they indicate that the reason for leaving the long leg was so that rotary trains could turn on the wye. Previous the the 20s, D&RGW rotary OM trains did not have the bunk, kitchen and other cars. The D&RGW wanted to turn the entire train without switching. That is also the reason for Lava Loop. The wye at Cumbres was not used for this purpose often as the OM rotary trains usually ran from Chama to Lava and return and the OY trains ran from Alamosa to Chama and return, but sometimes the rotary trains would turn at Cumbres and either return to Chama to back to Alamosa.