The Washington herald. [volume] (Washington, D.C.) 1906-1939, 1915-08-28

process not only Of the highest I'm.
portance. but one that 10 oftenttmes
very difficult to attain.
To briefly illustrate.-the controlling
rule termed the Rule of failure on
| the side of safety" provides that tho
removal. failure or arrangement Of
any essential part of the device or
system will reveal itself by displaying
the stop signal and cause the applica.
zion of the brakes
Therefore any cab signal and automatic
stop system proposed which does not
fairly meet engineering requirements will
not receive even a limited Investigation.
but will be promptly rejected upon mere
inspection
Importance of the railroad signal enxi-
neer. as this phase OF tho matter is
decided by him.
1t Is with this engineering aspect
In mind that the inventor in this art
must approach the problem.
The next problem of satisfactorily
producing either a mechanical or cleo.
trical method or means for transmi,-
ting an impulse from the track to the
locomotive to actuate mechanism.
thereon to stop a train is one of the
most difficult that has been proposed
in this art and has sorely taxed tho
ingenuity of inventors for . true solu-
ton thereof.
When an inventor employees q oer->
tain method or means to this end he
stamps his system as of q certain typa
and no matter how many reflnements
are incorporated in his system. tbs
general merit or demerit of his sys-
tenn is dependent upon the value Of tho
manner of obtaining this track Con.
nection.
From the fact that $500 Inventions
have been proposed in this art IL
would naturally be inferred that tho
as a matter of fact they can all be-
split up into four distinct typea a.
follows:
Four Distinct Types.
a. A contact obtained by impscs
or blow of a part on thetrack with Q,
part on the locomotive. which is callI
(0 yielding contact obtained By
the pressure Of a travelling part car
ried by the locomotive with a station
airy part on the track.-called the
az Transmitting an electric or mag,
netic impulse through the air, from the
track to the locomotive. called tha
as 4 rolling wheel contact obs
tanned by the presence of the wheels
Of locomotive on the trafic rails
Of action proposed by the first two,
types. it should be remembered that
all apparatus Con the track and loco
motive) is especially liable to materially
failure or breakage and 1t Is obvioun,
that a principle of action such - is'
proposed by violent mechanical blovo
delivered by a fast travelling locomo.
tive, to cause a hammer-blow contact,
Of the part thereon with q part on tho
track. hastens material failure and u,
mechanically considered q faulty model
of action because sooner or later failure |
or breakage of the parts will oocurt
as a result Of flaws developed In thsl
material due to such frequent ans
harsh treatment. Nine-tenths OF the
inventions that have been offered have
been based on such q plan OF obtain !
ing track connection.
The third or inductive method IL an 4
ideal one but the only system thust
far produced that has been tried out
on a railroad IL prohibitively expenstve'
and 1t has been found to require fur"
Their development
The fourth type Of system. tho rorls !.
ing wheel contact method. seems to bei
the most progressive and practical one
that has been proposed for establish. !
ing connection between the track ana
the locomotive. in that 1t provides
simply for the presence of the wheels
thereof on the naked trafic rails and |
REQUIRES no line wires or extraneousi
apparatus along the way.