cab signals in steam locomotives?

When PRR locomotives 7002 and 1223 ventured away from the Strasburg, 7002 was always on point because she had cab signals, while 1223 never did.

Britain's Great Western Railway used a form of cab signalling in its steam locomotives from 1906.

See Wikipedia and The Great Western Railway Automatic Train Control for details.

Cheers!
John

Engineer Spike wrote:B&M had cab signals too. New haven had two types of cab signals. A few engines had both systems.

From what I was told the NH had the 4 aspect (PRR) type system is use on the Shore Line while they had a two aspect type
(ala Illinois Central) on the Springfield Line.

"From what I remember from the history of this, a particularly nasty/deadly accident on the PRR (can't recall exactly where, but I think it was in Maryland or Delaware) was the reason this ruling was made by the ICC and implemented in 1922. Note that this was long before diesel-electric or electric power on the PRR."

I believe that the accident in question was the one that occurred in 1906 in Washington DC less than 1/4 mile from the Maryland & District boarder on the B&O.
"Deadly 1906 Washington DC Train Wreck Near Fort Totten"
http://brooklandavenue.com/blog/?p=845
Which occurred within yards of the accident occurring on the WMATA Red Line at Fort Totten on June 22 2009
http://en.wikipedia.org/wiki/Washington_Metro
The Red Line runs alongside CSX tracks that are also used by Amtrak (Chicago Limited) & MARC (Brunswick) that at one time was B&O right of way.
The cause of the Fort Totten wreck in 2009, was as I predicted within hours of the accident, an Impedance Bond (Z Bond) defect.
I thought that either the stopped train had stopped incorrectly positioned and was straddling it, hiding the signal, or that the Z-Bond failed (as they frequently do).
Anyway, the 1906 accident began the discussion that did not bear fruit until 1922 after there had been many more wrecks, likely including some nasty ones in the Northeast Corridor with PRR. The 1922 ICC legislation also mandated the first use of the Diesel Electrics. The rule required that Coal Fired Steam not be used within large metropolitan areas as a yard engine due to its heavy polluting coal dust. Many RRs used Tank Engines, but most used Diesel Electrics developed by GE, Westinghouse and Baldwin (jointly) as well as others.

I know this is a 3-year old thread, but a nice fun addition:

Nickel Plate 765 was upgraded with PRR cab signals in order to operate in the lead position across NS's Pittsburgh Division.

She has a 26L brake stand and even a cab-signal self-test system with an older 4-bulb designed cab signal box, opposed to a modern GE LED based device.

Well, we in Germany use a system called "Indusi", which is the short for "Induktive Zug-Sicherung", which translated to inductive train security.
Be means, you have electro magnets beneath the tracks and the locomotive has one below the cab each side.
The engines has to press a button at each signals, which affects speed or red lights.
Signals have magnets, and if a signal shows: "Slow ahead" and you haven't reduced the speed, the electromagnet affects the sensors in the locomotive, which rings a horn and opens an air valve: The engine will go to full stop by emergency brake. You only can reset after speed has been set back to zero.
If you pass a red signal, the same happens: Horn, air ventilation and emergency brake.

We have certain signals, each main signal has a call signal previous arranged, thus you'll know what to expect at the main signal. So if the caller shows "await halt", you have to press the quit button in the cap, as sign that the engine driver has seen the signal - if not, after a few Seconds: Horn, and energy brake.
If the caller shows "await slow ahead" - and you haven't pressed the button, you'll guess: Horn, emergency brake.
Only if the caller shows "free ahead" nothing is required...

In modern steam engines and air driven piston is attached to the throttle. If now the brake is applied, the air which activates the brakes will also activate the throttle cylinder and pull the throttle to close. On energy brake by Indusi, this will happen too

Thus you have a power knowdown... and as steam engines are driven in teams, well, you down need to shut down the engine completely - as the fireman operates the boiler manually and after emergency halt, he will know how to prevent any serious boiler incident...