Modelling the 1840s in HO

Very innovative Ian, well done!

Interesting model of an early signal.  Relatively simple but clever and effective.

Any plans for a working Railway Police flagman?

Yes, on the same principle - when the signalman is holding the red flag out sideways the driver has to stop. When the flagman is rotated through 90 degrees so the flag faces the driver (and so is invisible) the loco can proceed!

 

Neatly modelled Ian. Simple and effective for trains of the day but relied on the driver accepting road clear when he could see no stop signal. Safety was improved with the addition of a horizontal bar set at ninety degrees to the disc. This gave a definite road clear signal. 

5 minutes ago, Ohmisterporter said:

... Safety was improved with the addition of a horizontal bar set at ninety degrees to the disc. This gave a definite road clear signal. 

 

Yes, that must have been a big improvement - and it would be an easy feature to add to the model.

I think the Great Western adopted the safer disc and crossbar design fairly early, while the London and Croydon soon became a pioneer of the semaphore signal.

I think French and Belgian railways still used rotating signals into the 20th century, and I'm not sure that they had cross-bars. If not, I'd be interested to hear how they provided a definite signal that the road was clear ahead.

2 hours ago, Ian Simpson said:

 

Yes, that must have been a big improvement - and it would be an easy feature to add to the model.

I think the Great Western adopted the safer disc and crossbar design fairly early, while the London and Croydon soon became a pioneer of the semaphore signal.

I think French and Belgian railways still used rotating signals into the 20th century, and I'm not sure that they had cross-bars. If not, I'd be interested to hear how they provided a definite signal that the road was clear ahead.

French mechanical signalling has always been  based mainly on rotating signals though block signals were semaphores. I don't think much of it is left now (though there are some carrés- absolute stop signals- in use on busy days on the Baie de Somme) but  colour light signal indications still retain the names of their mechanical equivalents.

If you want to see an example of the first fixed signals used in France you'll find it at Didcot in the broad gauge area!  GWR disk and crossbars introduced in 1843 by the Paris-Orleans Railway's senior materials engineer named Clarke and as on the GWR the crossbar indicated danger and the red disk clear. These were used by the PO until about 1850 but the Paris-St. Germain railway adapted it to a red disk which was a stop signal operated locally by a gardien.  These and the other rotating signals soon introduced didn't have a crossbar or any other indication that they were open apart from the signal lghts that indicated their state at night.   The PLM introduced sémaphore signals based on, or at least inspired by, those developed on the London and Croydon and these became the block signals used generally. So, with French mechanical signalling, sémaphores were (and are) block signals indicating the state of the block ahead while the absolute stop signals protecting against conflicts, at junctions for example,  speed restriction signals, and the advance warning signals for all of these were rotating signals with differently shaped and coloured targets to indicate their meaning.

 

Though it started from the same early British technology, signalling in France developed on different lines. British signalling is permissive-a driver has to have permission from a clear signal before entering a section of track. French signalling is restrictive. A driver proceeeds according to their train order  until a signal gives a restrictive indication (that wasn't quite the same on single track lines) This meant that drivers did not get a definite signal that the line was clear ahead and with rotating signals, if the target wasn't visible there was no restriction. The French also use open rather than closed blocks- a train is clear to enter a block ahead unless it's occupied. This makes it far easier to close block posts at quiet times and station masters, who were generally responsible for signalling at smaller stations. didn't have to be constantly present at their block instruments. 

 

When the new Verlant signalling code was adopted in 1936, it called for signal lights on mechanical signals, previously only lit at night,  to be electric, permanently lit and colour light signals gave the same colour indications as lights on mechanical signals. Needless to say, with CLS (signalisation lumineux)  the lack of any indication is taken as a closed signal (as it would be in Britain)  so in practice the use of signals is not now so different.

Many thanks, @Pacific231G, the "Informative/Useful" button doesn't do justice to such a fascinating answer. I'm always intrigued by your explanations of early French practice, and I had absolutely no idea that the "restrictive" approach to signalling lasted so much longer in France. I've definitely learned something new today!

Edited May 15, 2020 by Ian Simpson

I had similar signals on my L&MR layout, and then one of the cats went a feasting on them, and the signals didn’t win that battle.

Early Liverpool & Manchester signals (1834), from models in the Science Museum:

The signal on the right had alternating red and green bars, the other signals were just red.

 

Edge Hill station in 1833 without a signal in sight:

Edited May 16, 2020 by Ian Simpson

11 hours ago, Ian Simpson said:

Early Liverpool & Manchester signals (1834), from models in the Science Museum:

The signal on the right had alternating red and green bars, the other signals were just red.

 

Edge Hill station in 1833 without a signal in sight:

I had a very hard time trying to find pictures of those signals, most were of American disc signals, ah the joys of my IP address.

I love this kind of modelling. A simple but effective solution, using burger skewers and coffee stirrers. Something to strive for, thanks Ian!

 

On 15/05/2020 at 15:56, Ian Simpson said:

Yes, on the same principle - when the signalman is holding the red flag out sideways the driver has to stop. When the flagman is rotated through 90 degrees so the flag faces the driver (and so is invisible) the loco can proceed!

 

You could model him in the same way 

 

57 minutes ago, Mikkel said:

... using burger skewers and coffee stirrers. Something to strive for, thanks Ian!

 

Many thanks for such kind words, Mikkel.

Although I should add my GP thinks my fast food diet is one to avoid, rather than strive for! 

On 15/05/2020 at 20:32, Ian Simpson said:

Many thanks, @Pacific231G, the "Informative/Useful" button doesn't do justice to such a fascinating answer. I'm always intrigued by your explanations of early French practice, and I had absolutely no idea that the "restrictive" approach to signalling lasted so much longer in France. I've definitely learned something new today!

They still use open block, a block is open for a train to enter unless it's occupied or closed for some other reason. The main effect of that is that the block post behind doesn't have to offer a train to the block post ahead though, once a train has entered and occupied the section, the post ahead has to confirm that it's passed before it can be cleared. But, if you think about it that's how automatic four aspect signalling works in Britain. After a train has passed, the signal goes red, then yellow, then double yellow then green as it moves away section by section.