Great Western Coffee Shop

In the very early days, different coloured lights were used if compared to modern practice in signals at night.
Red for stop or danger was used from the early days.
White was used for clear or proceed in the early days, dangerous by modern standards since an extraneous white light could be taken as the signal to proceed.
Green was used for caution. Green lights tended to be very dim, since modern types of blue/green coloured glass had not been developed.
A little later, the original GWR used purple lights for proceed on some freight lines, this to avoid confusion with the green for proceed on adjacent main lines.

A variety of flashing lights were trialed for railway signaling purposes, but not adopted on a large scale. To produce a flashing light before electric lights was an achievement. The AGA company made flashing acetylene lights, some were used until recently for marine warning lights, and may still be in use.

Overseas, some use was made of flashing red lights for warnings. These used oil lamps designed to flash, or at least flicker, two or three times a second. (used into at least the 1960s in the USA as warning lights around road works, believed extinct on railways)

Some early semaphore signals were controlled by overhead steel wires, operated by levers in the signal box,rather than the still extant practice of ground level wires.

https://en.wikipedia.org/wiki/Express_train#/media/File:Earlyballsignalsketch.png

The ball signal was a very, very early signal on American railways. When hoisted up was proceed and down was danger; so i suppose very early failsafe.

It featured in the TV western episode of Cimarron Strip, "The Blue Moon Train". The series was set in 1888 but I wonder if it was still in use.

My understanding is that there was a wire to pull the signals to clear and another wire to pull them to danger - a very real problem if the pull-to-danger wire snapped and left a false clear.  Even when signals became pull-to-clear and return to danger via a counterweight or if the wire snapped, there were issues such as at Abbot's Ripon where snow and ice held the wire and a train ran through to a collision, made worse by a second train ploughing into the wreckage on the double east coast main line.


Is this the ancestor of the ball falling at midnight on New Years eve / day at Time Square, New York, signalling in the New Year?

It was the derivative of the term "Highball" for an American Express (https://en.wikipedia.org/wiki/Highball_Signal) train.

Old photos of early GWR signal boxes show the signalman exhibiting a white flag to passing trains in addition to the fixed signals.

Facets of the old red-green-white continue to this day. When shunting at night using a hand lamp on Britain's railways a white light is used for normal shunting and a green light for shunting at reduced speed.

On the Isle of Man Railways, on departure, the train complete signal from the guard at the rear of the train is a yellow flag. On checking the old rule book this is a substitution from the original white flag specified. White railway flags are not made anymore and they are difficult to keep clean!

PS 'Signaling' is the American spelling!

'tis all here :

https://en.wikipedia.org/wiki/Time_ball