garethashenden wrote:The NLR seemed to have used LNWR signals, but did it use them exclusively? I have a copy of LNWR Portrayed, which has a largish section on signals, but before I dive in and copy it it seems advisable to find out if the NLR did things their own way...
The LNWR only took over the NLR signalling department in 1909. "The Signal Box", by The Signalling Study Group, published by OPC [two editions at least] is rather vague about earlier practice, apparently due to lack of original sources. It does state that: Absolute Block working was in use by 1855 [probably implying also, therefore, that lines built subsequently would have used absolute block and would have been fully signalled], and the line was fully interlocked before the first BoT return in 1873; little is known about the design of the boxes, but work was put out to competitive tender with several contractors and some contractors' boxes are known; NLR box designs were used from 1870 onwards. The book doesn't cover the actual signalling, but this would presumably be to contractors' design(s) before the NLR started to do the work themselves.
garethashenden wrote:So I need some signals for my intense goods service, because crashing trains into each other is bad for business. I have a total of four points. If I tie two of them together as a crossover, do I still need a catch point? I would hope not as there isn't room. The other end of the yard will need a catch point. Not the end of the world, the first point on the layout needs some attention anyway so the catch point can be added in. Then I need a couple of facing point locks and at least two signals.
Assuming that you do not run a passenger service then catch points are not legally required. However, this is the sort of situation, with a busy main line, where any sensible operator would put one in at the LH end. The crossover is OK to protect the other end on the basis that the line at the back is the only main line. If you intend the loop to be a main line crossing loop then the situation potentially becomes much more complex; it depends how far you want to take it. As it is, there is not enough room to put a single catch point on the loop after the siding point [the trap has to be before the main line fouling point], so a railway engineer would put the catch blades in both roads before the toe of the point.
garethashenden wrote:Then I need a couple of facing point locks and at least two signals.
Again assuming no passenger service, fpls are not legally required, but could sometimes be used for safety reasons.
garethashenden wrote:I found the comment about the BoT's view on single track lines to be very interesting and something that I will bear in mind for future layout plans. Its quite contrary to the standard practice in America, which is what I'm most familiar with. Here railroads were hastily built single track lines that only got expanded later if the traffic levels required it.
In the UK, unless they were entirely on the builders' own land and not intending to carry the general public, railways required a private Act of Parliament before building. This had two primary purposes - it enabled the railway to get authority for compulsory purchase of the land required, subject to conditions, and it allowed Parliament to check objections to the scheme, the engineering involved and the route, including, for example, the gradients. What they checked and how much did tend to vary over time, but this was the usual minimum. The Board of Trade had the responsibility of overseeing railway operation in the UK, including investigation of railway accidents, and developed what today might be called 'best practice'. They were advocating "lock, block and brake" [interlocking frames, absolute block signalling and automatic power brakes] well before Parliament gave them powers to compel their installation on passenger carrying lines after the Armagh accident in 1889. Some companies paid more attention than others; the NLR seem to have been one of the more virtuous.
The BoT also required companies operating single lines to certify in writing that only one engine in steam, or two coupled together, would be allowed in any single line section. Following some nasty accidents on single lines operating with "staff and ticket" or "telegraph and crossing order" systems, signal engineers from the late 1870s introduced various electro-mechanical systems involving 'electric' staffs, tokens or tablets to make it impossible [in theory] for two trains to be in the same section. Human error still managed to cause problems even then of course...
Public railway lines with busy single main lines for freight only were probably rare in the UK in that era; most single line, goods only, situations were low speed locations operated as sidings or by telegraph/telephone and shunter's authority for movements. For a busy single track goods only line I would think it likely that the company would apply the same equipment and rules as for any other single line.
Incidentally, there is a Society for the NLR; I don’t know anything about them, but they have a website
http://www.nlrhs.org.uk/.