ed. The hands are then set at the correct time, and the
alarm fully wound.

XIII. A MODEL ELECTRIC RAILWAY.

The rapid increase in the number of electrically worked railways, and the
substitution of the electric for the steam locomotive on many lines, give
legitimate cause for wondering whether, twenty or so years hence, the
descendants of the "Rocket" will not have disappeared from all the railways
of the world, excepting perhaps those of transcontinental character.

[Illustration: Fig. 41.--Electric Locomotive.]

The change is already spreading to model plant, and not without good
reason, as the miniature electric railway possesses decided advantages of
its own. Instead of having to chase the locomotive to stop or reverse it,
one merely has to press a button or move a switch. The fascinations of a
model steam locomotive, with its furnace, hissing of steam, business-like
puffings, and a visible working of piston and connecting rods, are not to
be denied, any more than that a full-sized steam locomotive is a more
imposing object at rest or in motion than its electric rival. On the other
hand, the ease of control already noticed, and the absence of burning fuel,
water leakage, smoke and fumes, are strong points in favour of the electric
track, which does no more harm to a carpet than to a front lawn, being
essentially clean to handle. Under the head of cost the electric locomotive
comes out well, as motors can be purchased cheaply; and connecting them up
with driving wheels is a much less troublesome business than the
construction of an equally efficient steamer. One may add that the electric
motor is ready to start at a moment's notice: there is no delay
corresponding to that caused by the raising of steam.

The Track

We will consider this first, as its design must govern, within certain
limits, the design of the locomotive. There are three systems of electrical
transmission available.

1. The trolley system, with overhead cable attached to insulators on posts,
to carry the current one way, the rails being used as the "return." This
system has the disadvantages associated with a wire over which the human
foot may easily trip with disastrous effect.

2. That in which one of the wheel rails is used for taking the current to
the motor, and the other as the return. The objection to the system is that
the wheels must be insulated, to prevent short circuiting; and this,
besides causing trouble in construction,