Omaha daily bee., 1908-11-08
Locomotive Cab Signals.

I'M
The following is a description Of the sys-
tenn OF cab signalling now under trial on
the Great Western railway Of England
The system has been in use for the drivers
on the Hartford branch (twenty-one miles
long, since December, 1906, when the sema-
phore "distants" were removed by sanction
Of the Board of Trade. The Great Western
officials are now completely fitting their
four main tracks between Slough and
Reading with the apparatus. The require
ments to which all signalling systems of
this character must conform are: a. that
the signal shall be audible, and given in
the cab OF the engine; (2) that two indica-
lions shall be given according to the state
of the line ahead-one for "all right" and
another quite distinct for danger" 60
that in the event Of failure, IL the appa-
ratus is wholly or partially electrical, the
danger signal shall be given-in other
words, such an apparatus should, If 1t errs
at all. err on the right side; "a that there
should be no moving parts on the track;
~ tina the signal, when given. shall con-
tinue to sound until acknowledged by the
driver shutting It off. At each distant
signalling post a ramp Is bolted to tho
sleepers midway between the rails, so that
a oAiOO Oh NAhO Nh0AAAS hhoy w AhANNAl "ASNAAN
the engine is running tender or funne
first. This ramp cannot be moved, and its
function is primarily to lift a shoe placed
on the engine for the purpose every time
the engine passes over It. The ramp is in
clined, with a rise of about two and a half
inches in thirty feet. so that the blow
struck by the shoe when the contact takes
place is reduced to a minimum. In con-
nection with the shoe on the engine there
is an apparatus for operating either a
special steam whistle or an electric bell,
according to whether the signal is to indi-
cate danger" or "all right" This APP
paratus consists briefly Of a closed circuit
when the shoe is in its normal position.
the electro magnets connected Herewith
having, when energized, sufficient power
to prevent the steam whistle from open
ing. Surprising the signal to be at dan
ger when the ann IL reached. the shoe
will be lifted; when lifted, II will meehan
icslly break the engine circuit above re-
ferred to. When the circuit is broken, the
restraining force is removed from the
whistle, and, being of the self-operating
type, the whistle sounds until stopped by
the driver. The "all right" signal is given
In the following manner, and in this lies
the chief value OF the invention. When II
is desired 10 give the "ail right" indiea-
ton, the signalmsn pulls over his distant
signal lever. This action closes another
circuit which electrifies the ramp, and.
when the engine shoe touches it, causes
a curreht to Flow through the shoe and
through another pair Of coils having equal
power with the pair before referred to,
and forming, besides, a circuit through
an electric bell. Thus, although the lift-
ing of the shoe should, in the ordinary
way. break the local circuit on the engine,
and thus cause the whistle to sound, this
result is prevented by ~energizing an aux
Hilary pair Of coils direct from the en-
giae box. and in addition the signal box
circuit passes through the bell. which con-
tinues to ring until stopped by the driver.