152 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1907. 
Almost the entire weight of the locomotive is spring borne, and 
the behavior of the machine on curves even at high speeds ought to 
be very satisfactory. The same general construction would lend 
itself very effectively to the application of high-tension inter-pole 
direct-current motors, and may be very seriously considered in this 
connection. 
The general characteristics of the New York Central type of loco- 
motive (pl. 1), the Batchelder machine as developed by the General 
Electric Company, is pretty generally understood, and my description 
will be limited. It consists essentially of a heavy steel frame in which 
are journaled four main axles, and which is terminated by pivoted 
Wig. 4.—Longitudinal section—bipolar direct-current motor. 
single-axle ponies provided with spring resistance against deflection 
from the central position. The motors are the gearless type, the arma- 
tures being mounted directly on the axles (Pl. VI) and the bipolar 
field magnets forming an integral part of the main frame; they are, 
therefore, carried with it by the equalizing springs, and have free 
motion relative to the armatures. In addition to the regular truck 
frame, an additional path is provided for the magnetic flux, which 
passes through all the armatures and field poles in series, by a heavy 
bar extending the length of the frame, and carried above the motors. 
3eing of the two-pole type (fig. 4) and with a quadrant winding, 
the motors are extraordinarily free from sparking tendencies; in fact, 
they are, structurally, natural 1,200-volt machines, although only 
wound for present operation at 650. So marked is this characteristic, 
that the brushes, which are 180° apart, instead of being carried on 
