Mac Poor in his earlier excellent book indicates there was an existing wagon road from St. Elmo to Handcock and the general opinion was rail would be laid to the East side of Alpine Tunnel before the Tunnel was completed. He does mention the construction camps on both East and West side of Alpine Tunnel with a few details.
Perhaps early right of way grading provided access from Handcock to the Tunnel before rail was laid instead of building a new wagon road to the construction camp on the East Side? There isn't much flat ground on the East side of Alpine Tunnel that probably dictated where the camps were located. Mules on a trail without a wagon road were commonly used for years in Colorado to transport (or drag on one end) larger and longer timbers for Mines and Mills than used for the interior of Alpine Tunnel.