Abstract
The author was recently engaged by the Denver and Rio Grande Western Railroad to make a study of the ventilation of the Moffat Tunnel, which is 6.21 miles in length. In the course of this work measurements were made of the friction of air through the empty tunnel and also of the air pressures developed by different trains of various lengths passing through the tunnel at speeds ranging from 15 to 38 mph. The results of this investigation are presented in the form of curves for a wide variety of conditions. The mathematical analyses are given, which may be applied to the problem of tunnel ventilation in general. For the reason that but little information concerning the subject of “piston action” of trains in tunnels is available in the engineering literature, the author deems it desirable to make the present data a matter of record.
