SPEED SIGNS

[Bryan]

As it is chucking it down I was flicking through a 1974 Bradford Barton North Eastern Pacifics, and on p78 I noticed an unusual speed restriction sign. 8 mph
This would have been at Platform end (which one I do not know) for the approach to the tunnel.
It is not a temporary restriction but a permanent limit.
My query is why 8?
Why I am asking is that as part of my work I attended a P Way track design course and all speeds are rounded to the nearest 5.
Was it deemed as too slow for a 5 but too fast for 10 through the tunnel?
Can any one provide an answer?

[stembok]

Interesting point. Would it have been the throat at King's Cross and the approach to Gasworks Tunnel? There used to be an 8 mph restriction I believe at this point. But why did they arrive at 8? After all in the days before speedometers -and even after they were introduced - it must all have been fairly academic, the difference between say 5 and 10 mph.

[Bryan]

The photo shows an UP arrival from Leeds - Bradford behind 60130 Kestrel.
There is in view a longer platform to the right East side with buildings on it, then possibly 3 tracks an island platform. Above the only coach visible in the train can be seen a parapet wall possibly the top of the tunnels.
So yes it would be at the throat applicable in the Down direction.

[R. pike]

I think it was 8 mph because the sign could be read from both sides. The only other number you can do this with being 1 i think is a little too restrictive.

[Flamingo]

Don't know if it still exists, but another instance of an 8 mph speed restriction was over the swing bridge at Clachnacuddin just outside Inverness on the North Line.

[Flamingo]

Don't know if it still exists, but another instance of an 8 mph speed restriction was over the swing bridge at Clachnacuddin just outside Inverness on the North Line.

Correction: that should read Clachnaharry

[Bullhead]

The current Sectional Appendix shows that there's a PSR of 10mph over Clachnaharry swing bridge.

[Bryan]

( I think it was 8 mph because the sign could be read from both sides.)
I don't think that is the case here as there is a signal about 3 yards away which would obscure it.

[R. pike]

The place was littered with 8 mph speed signs..
http://www.gngen.fotopic.net/p46986422.html
http://www.gngen.fotopic.net/p48273237.html

[hq1hitchin]

Did the 8 mph signs have arrows associated with them? One of my LNER friends, traffic not p.way, mind, reckons the general speed limit between the tunnels at KX and the platforms was 15 mph due to the very cramped layout and what have you - so if we accept that a halving of that speed though a diversionary route is prudent (as indicated by the arrow), given that most locomotives were then without speedos, that gives us 7.5 mph - let's make it 8 then, does that sound reasonable?

However, I have just dug out my 1947 Sectional Appendix and find that some of the foregoing may not be exactly correct because at that time, and it seems incredible today, there was a speed limit of 'caution' (whatever that speed is) for 'trains on Main Line from North End of Gasworks Tunnel to Nos 1 to 5 Platforms' with an 8 mph PSR applying to 'Other Trains between Station and South End of Gasworks Tunnel'. At the top of Table A, we are referred to P61 of the General Appendix and this tells us that a standard restriction of 15 mph will apply 'on double lines when passing through junctions between parallel lines, or through crossover roads, or when leaving or entering loop, independent, platform or bay lines' so perhaps our correspondent's logic regarding the reduction of the normal speed of 15 mph when going through crossovers etc. (with which drivers would be very familiar at other locations) by half is correct when we come to deducing how the unusual speed of 8mph was arrived at. Remember - 5 mph is only for depots and sidings, hardly appropriate for a main line station!

[Bryan]

No arrows are evident in the photos.
Also they appear to be for traffic departing from the station.