Onslow sidings Cornwall between Bodmin road and Doublebois

[john.wickens]

Can anyone explain why the clay dries' siding had a gate protecting it at the western end but not the western end of the siding, what was the purpose of the gate ? Also given the reported fact that the down distant signal had the longest wire pull in Cornwall - over a mile long, was it designed with counter weights along its length, other wise I can't visualise how a signalman could operate the signal ?
With thanks,
John Wickens
Harrogate, North Yorkshire

 

[Gloster]

Looking at Section 11 of Cooke’s diagrams (2019 edition), Onslow Siding is shown as having gates at both ends of the layout just inside the points leading to the main line. This would seem logical if the siding was a private one throughout its life. Gates were a fairly normal way of indicating the boundary between railway and other ownership.

 

[John Webb]

.....Also given the reported fact that the down distant signal had the longest wire pull in Cornwall - over a mile long, was it designed with counter weights along its length, other wise I can't visualise how a signalman could operate the signal ?
With thanks,
John Wickens
Harrogate, North Yorkshire

A mile-long pull for a distant signal was not uncommon around much of the country. The distant to home signal distance was controlled by a number of factors including the linespeed, type of trains, gradients and any signal sighting problems.
Some runs of wire for distant signals included 'Gain Stroke levers' which compensated for 'lost motion' in the wire - a vertical lever, pivoted at the top on a lineside post, had the wire from the box attached at one point on this arm and the wire to the signal at the bottom of the arm. Thus the wire running to signal was moved more than the point on the arm to which the wire from the box was attached; no counterweights were employed.
Long runs of signal wire (some 'home' signals could be some distance from the box as well as the distants) could also be catered for by running the wire (normally a chain at that point) over a wheel attached to the lever effectively doubling the stroke of the lever.

 

[Sir Felix Pole]

Cornwall Railway Soc. has a section on Onslow Sdgs, including a good shot of the box shortly before closure in 1968.

Onslow Sdgs

(Scroll well down to find it as the sections are not indexed).

Additional information kindly supplied by Roy Hart
Onslow box opened on 31st January 1931 to serve the Bowaters clay worķs there. The layout consisted of a long loop siding and a second, gated loop for the works. The box was normally switched out throughout its life, only opening for siding traffic on one or two days a week for a couple of hours.
Two historical features of the place: Onslow was the first complete installation of tubular steel signals on the GWR (they had wooden arms though) and secondly, Onslow lay at the foot of the long descent from Doublebois, so the down distant signal had to be a long way out. At 1920 yards it was the longest 'pull' in Cornwall.

The bos was of what the SRS calls 'type 28B'. It arrived 'flatpack' style and was erected in a day. The box closed on 10th November 1968.

 

[Gloster]

One of the problems here is that the three sources that I can find (Cooke’s diagrams, the Signalling Record Society’s signal box diagram and the Cornish Railways Society’s site) do not agree. I would personally give preference to Cooke as he did a lot of research from original sources. However, original sources do not always reflect the situation on the ground and throughout the period concerned. One small doubt in my mind is whether the second gate was right down by the points at the east end of the main siding, as on Cooke, or adjacent to the points to the shorter loading bank loop siding, as suggested by the CRS’ site.