Forest Hills-Everett (via tunnel) 8.59 miles Forest Hills-Everett (via elev.) 9.35 miles Harvard-Andrew 5.56 miles No. Station West-Kenmore 2.87 miles Bowdoin-Maverick Sq. 1.67 miles The Forest Hills-Everett route is called the main line, and the Harvard-Andrew route the Cambridge Subway. The Bowdoin-Maverick Square line up to the present has been operating three-car trains with overhead trolley, but new equipment consisting of steel cars is now on order and the third rail is now being installed in the tunnel. The Lechmere Sq.-Broadway line over East Cambridge Viaduct and Tremont St. Subway is also considered a rapid transit route, although surface type cars are used with overhead trolley. These cars are equipped for multiple unit control and are operated in three-car trains. [Illustration: 35,000-KW. TURBO-GENERATOR IN SOUTH BOSTON POWER STATION] The rush hour trains on the main line include as high as eight cars, which is the limit set by the length of the station platforms. The signal system is entirely automatic and during rush hours the headway varies from 2 to 3½ minutes on the main line. The maximum grades encountered are 2 to 3 percent with a high percentage of heavy curvature. By taking advantage of the transfer arrangements at terminals, rides of 14 miles can be obtained for a single fare. _Power Station Equipment_ The power system as originally installed included several engine-driven direct-current plants suitably located for distributing 600 volts direct to the trolley. With the extension of the system, however, an alternating-current station was installed at South Boston, generating 25-cycle three-phase current for distribution at 13,200 volts to synchronous converter substations. Alternating-current generating equipment has also been installed at the Lincoln Station. The total installed capacity of turbine stations is now 115,000 kw. while the direct-current generating stations have practically all been discontinued. [Illustration: RAPID TRANSIT LINES—BOSTON ELEVATED RAILWAY] [Illustration: EXTERIOR OF EGLESTON SQUARE SUBSTATION] _Substations_ There are in operation for supplying power to both elevated and surface lines a total of 12 synchronous converter substations having a total rated capacity of 58,000 kw. The power consumption of the Rapid Transit lines is somewhat less than half the total energy used. _Distribution_ Direct current is distributed from the several substations at 600 volts and is collected on the rapid transit systems from an 85-lb. over-running third rail. _Rolling Stock_