The summit tunnel (Number 6), , was started in late 1865, well ahead of the railhead. Through solid granite, the summit tunnel progressed at a rate of only about per day per face as it was being worked by three eight-hour shifts of workers, hand drilling holes with a rock drill and hammer, filling them with black powder and trying to blast the granite loose. One crew worked drilling holes on the faces and another crew collected and removed the loosened rock after each explosion. The workers were pulled off the summit tunnel and the track grading east of Donner Pass in the winter of 1865-66 as there was no way to supply them, nor quarters they could have lived in. The crews were transferred to work on bridges and track grading on the Truckee River canyon.