Kenya - semaphores

[John Ashworth]

Photos by John Ashworth around 1996 or '97

[Steve Appleton]

A three aspect semaphore? Danger - level, caution - 45deg, all clear - vertical. That right?

[John Ashworth]

I'm not sure, actually, Steve. I don't know whether it's three aspect, or whether it simply doesn't have a 45 degree position - only horizontal and vertical. Hopefully somebody out there on the forum can tell us?

[Chris Janisch]

Are semaphores still in use throughout East Africa?

[John Ashworth]

I don't know, Chris. There seem to be some still in use in Kenya, although there are also some colour light signals. It's a long while since I've looked at railways in Uganda or Tanzania. There are still semaphore signals in Sudan.

[Steve Appleton]

Nice if someone could clarify.
In the centre of the three pics, the upper semaphore arm distinctly has 3 lenses, red, yellow and green. It would appear that it can display all three aspects.
The lower arm on the same post has only two lenses, red and yellow - presumably danger at horizontal and caution at 45. I guess this signal acts like a distant, showing danger and caution only.
The top pic shows the top arm at all clear - vertical.
The lower pic shows a semaphore arm with what also looks like only two lenses, red and green in the horizontal and vertical positions only. The intermediate centre position appears to be blanked. Presumably this signal can only display the two extreme aspects, danger and all clear, like a home signal.

[Steve Appleton]

Looking at the centre pic again, it would appear that the top arm is for the through road, whilst the bottom arm is for the loop. Standard practice in the UK and SA too. This would explain why the bottom arm has no 'all clear' position: there is a turn out to be negotiated into the loop.
I also notice that what seems like the 'starter' signals are not semaphore arms, but disk signals (similar to those found here but black and yellow), one of which is set to clear and the other to danger.

[John Ashworth]

Well spotted, Steve. I hadn't noticed the lenses. And you're right that the lower arm is for the loop.

Those discs might be route (points) indicators, not starting signals. If the train control in Kenya is anything like in South Africa, then you wouldn't normally find starter signals on single track. Dagoretti Station has a station master and token equipment, so presumably the driver would be given authority to proceed by the station master giving him the token.

[Steve Appleton]

Yes, John, you would be right then, the discs would essentially be points indicators. My guess is that by using 3-aspect semaphores, they saved on the need for a separate distant signal, probably relying on a 'warning board' of sorts further out as is also done in some places here.

[Kevin Wilson-Smith]

The original signaling system was based on Indian Railways - but that says nothing as I cannot tell you what system they used in India at the turn of the century!n Probably basically a UK one?

The reason for the above was both the engineers - construction that is -in the main came from India Railways, as did the signaling and station and yard staff.

[Steve Appleton]

Just found this about Indian Railways signalling http://www.irfca.org/faq/faq-signal.html, which seems to confirm the use of three aspect, upper quadrant semaphores there:

IR uses several kinds of signals. Semaphore signals have generally given way to colour-light signals although there are still many places with semaphore signalling in use. [1/02]

Semaphore signals are the older style signals seen widely throughout the country, where each signal has an assembly with an arm mounted on a mast, where the arm can move through two or three different positions at different angles, each position providing a distinct signalling aspect. Very early in India's railway history, two-position lower-quadrant semaphore signals were the most prevalent. Around the 1930s, however, the introduction of American style power signalling equipment in some areas resulted in three-position upper-quadrant signalling being introduced as well, although both systems continued in use for many decades afterwards. It is not clear when distant signals were introduced.

[Steve Appleton]

You are right about the Indian practices. I do not know of anywhere in the UK where multiple aspect semaphores were used and, following British practise, they are not used here either, so far as I am aware.
The Indian Railway page goes on to describe those signals and refers to: Multiple Aspect Upper Quadrant semaphore signalling (MAUQ), thus:

Upper Quadrant
Properly, Multiple Aspect Upper Quadrant, in this system there are three signal positions. The 12 o'clock position is clear or proceed, which gives a train permission to go past the signal without stopping. An intermediate position (at 45 degrees to the vertical) is the attention or caution indication; the meaning depends on the kind of signal. The horizontal position, where the semaphore arm is horizontal, the on position, is the most restrictive indication of the signal; it may require the train to stop, or to proceed with caution, etc., depending on the kind of signal.

More notes: In all semaphore systems, as the semaphore arm moves from one aspect to another, the end that is close to the signal mast and which has coloured glass disks ('spectacles') fixed to it moves in front of a lamp, changing the colour of the lamp seen at night. Today most of these lamps are electric lamps, but oil lamps were common earlier.

Semaphore signals are set up so that when viewed from the part of the track for which the signal is intended, the semaphore arm extends to the left of the mast on which it mounted. This, in addition to the colours of the semaphore arm (which are different on the front and back), provides a visual cue to distinguish between the signals meant for different directions of the track.

Assemblies of 2 or 3 or more semaphore signals on the same mast structure occur to indicate divergent routes. Usually, one of the signals is placed higher than the others, to indicate the 'main' line; the signals to its left or right are somewhat lower, and apply to signals to branches diverging to the left and right. Signals may be at the same height if the divergent routes are all of the same importance. Such multiple signal assemblies are seen for stop signals (home, starter, etc.) and also for distant signals (pre-warners).

Multiple Aspect Upper Quadrant Signalling

mauq.gif (6.83 KiB) Viewed 6858 times

[John Ashworth]

A few days ago I had a good chat about railway operations with Kenyan railwaymen at Konza Station and they confirmed that three-aspect signalling is used. We were standing looking at a starter signal and they told me that starter signals only have two positions - proceed (vertical) and danger (horizontal). But I forgot to ask them why/how starter signals are used on a single track line where the driver is given a token as authority to proceed - ah well, next time.