which have also been standardized by Mr.
Koppel. A specimen of these posts with an anchored stay is shown in
Fig. 4. All these details are arranged for convenience of the
contractor required to rapidly equip a line of railway, which can also
be removed as soon as the work has been done.

[Illustration: FIG. 4.--LIGHT POLE FOR CARRYING THE FEEDERS.]

[Illustration: FIG. 5.--THE KOPPEL LOCOMOTIVE.]

The locomotive used is varied in form with the gage of the line, but
we are particularly concerned with those for gages under 24 inches.
One form of such locomotive without a hood to protect the driver is
shown in Fig. 5. In this locomotive the gear is the same as that of
the next illustration, but it is securely boxed in a watertight iron
cover. The controlling gear is then placed vertically in front. Figs.
6 and 7 show the details of the electrical and mechanical parts of
this locomotive when fitted with a platform at either end, and with a
hood. The motor. M, is of the internal pole type, and is supported on
the underframe of the wagon. A double gear is used. The first is a
spur gearing, connecting the motor to a countershaft placed under the
motor. This gear reduces the speed of rotation to about 200
revolutions. The countershaft is then connected to the two axles of
the trolley by chain gearing. This gives the necessary flexibility
between the car body and the wheel required, as the springs give to
any inequality of the rails. In this gearing there is no change of
speed. The underframe is provided with spring axle boxes, and also
with spring buffers and drawbars. The speed of the motor can be
regulated within very wide limits by the regulator, R. An effective
hand brake is also provided.

[Illustration: FIG. 6.--END ELEVATION OF LOCOMOTIVE.]

[Illustration: FIG. 7.--DETAILED ELEVATION OF A KOPPEL LOCOMOTIVE WITH
A DOUBLE PLATFORM AND HOOD.]

For gages of 20 inches and upward the motors can be mounted on springs
and attached to the running axles inside of the wagon underframe. This
construction is particularly recommended by Mr. Koppel where, in order
to mount heavy gradients, the dead load of the motor car must be
assisted by the paying load to produce the necessary adhesion. In such
cases several motor wagons would be used in the same train. As regards
the working voltage, this can be varied to suit special requirements,
but the locomotive we illustrate was designed for 110 volts. At this
pressure its possible wo