Intra City Traffic.
—Mr. J. C. Thirlwall, of the railway and tractive engineering department of the General Electric Company (General Electric Review, Vol. XXIV, pp. 974-985), discussing the fields of the rail car, trolley bus and gasoline bus, tabulates the respective costs of these types on a comparative basis for a variety of conditions. In general the calculations indicate that:
(a) Where rush hour headways of 3 min. or less are required with safety cars, rail cars are the most economical and up to 6 min. headways offer successful competition to the other types where the road is a going concern.
(b) On longer headways the trolley bus appears to have the advantage due to the lower fixed charges.
(c) The gasoline bus on account of higher operating expense does not offer competition to the rail car until minimum headways of 10 min. are reached on new routes and 20 min. on existing lines.
(d) The trolley bus is more economical than the gasoline bus up to headways of 60 min. or longer.
A tabulation of the respective fields is as follows:
Minimum headways, 3 min. or less; rail cars.
Minimum headways, 3 to 6 min.; rail cars or trolley bus.
Minimum headways, 6 to 60 min.; trolley bus.