Shearer p. 245 “between Tamarack and Cisco, Red Spur and Trap Spur are passed by tunnels No. 4 and No. 3.”
Crofutt p. 164 “[from Tamarack] among the hills, through the snow-sheds and tunnels, we speed on for three miles, when we arrive at Cisco”
Hart’s photograph captures the raw appearance of the early tunnel, which has since been expanded to allow the passage of larger trains and a double track.