Jeremy Cumberland

Why wouldn't they both be on Annett's keys? It by far the simplest arrangement. Is there any reason why both crossovers should be reversed at the same time?

I cannot tell one GWR class from another, but the position of "Y of" means that the second word is shorter than the first. County of Hants is therefore a likely possibility, and I think the only other possibilities (if the number does end in 5) are 3475 County of Wilts and 3835 County of Devon. These were both renumbered in 1912, with the former being pre-1912 and the latter post 1912. Perhaps on the original photograph the first letter of the county name is clear enough to rule these out.

Let me get this straight: It is a single line. As you head from left-ish to right-ish in your top pictures, there is a platform, then the level crossing, then the facing siding point. You will have track circuits and/or treadles for normal train operation (not using the siding) - your real life example clearly has track circuits as you can see from the last but one photo - with most likely a pushbutton or similar on the platform to activate the crossing for trains heading left to right, assuming all trains are likely to stop in the platform anyway. Apart from this, all you need is a pushbutton or similar to activate the crossing before a train leaves the siding. It probably makes most sense for this to be by the ground frame, and operated by whoever operates the ground frame. Both activation devices need to be secure from being tampered with. There are only six possible movements that I can see: Left to right on main line: Train stops in platform and driver operates activation device. Right to left on main line: Automatic operation by track circuit and/or treadle. From left to siding: Train stops in platform. One person operates ground frame. When line is set, driver operates crossing activation device on platform. From right to siding: Automatic operation by track circuit and/or treadle. Train stops in platform clear of crossing. One person operates ground frame. The same person then probably walks back to platform and operates the activation device on the platform (assuming the driver is at the other end of the train). Train shunts into siding. From siding to left: One person operates ground frame then operates activation device by ground frame. Train enters platform. Ground frame reset and train continues when person is on board. From siding to right: One person operates ground frame then operates activation device by ground frame. Train reverses into platform clear of the crossing. Ground frame reset and person rejoins train. Driver operates crossing actuation device on platform. Train leaves.

They are check rails for dual gauge. Here is a picture showing what the whole thing presumably looks like, although this example is from Australia rather than Austria. show

They're in steel, so I doubt it matters. In wood, a tenon joint is far stronger in compression than it is in tension.

I imagine much of the Hornby range is EN71 certified, and they are members of the British Toy & Hobby Association, so they could apply the logo quite widely to their products. However, I also imagine that they choose not to because they don't want them thought of as being "children's toys".

If you are doing DC voltage testing (which the OP is) then having the wires the wrong way round will show -12 V instead of 12 V, for example. If you aren't interested in polarity then this does not matter, but the OP specifically asked about testing the polarity of his PSU outputs. You will get a similar polarity error with DC current testing. If you are doing resistance, continuity or diode testing, where the meter applies a voltage across the two probes, if the leads are plugged in the wrong way round then the black probe will be positive and the red probe negative. This won't make any difference unless you are testing electronics (diodes and transistors), when you will get unexpected and possibly confusing results (till you work out the leads are swapped over).

This isn't true. Power does not usually remain constant regardless of voltage, and power ratings are usually given as the maximum power expected at the usual voltage. With tungsten filament incandescent bulbs, there is a sudden current draw when they are turned on which quickly heats up the filament and increaes the resistance, which in your example ends up as about 400 ohms. When cold, the resistance is a lot less, perhaps 30 ohms. from which we can work out that the initial current at 12 volts is 0.4 A. This is enough to heat up the filament, increase the resistance and so reduce the current, perhaps to 0.1 A, making the power of the 1.2 watts at 12 volts. The bulb will barely glow. These numbers might not be accurate but they should be in the right ball park. Don't use a multimeter with mains voltages unless you know what you are doing. You also need to take a little more care with current readings, and sometimes a lot more care with the meter set to measure resistance, than you do with voltage readings.

If you are using a proprietary PSU, then you need have no concerns about safety. Short of cutting it open you won't be able to get anywhere near the mains voltage, and 12 V (or even twice that) won't cause you any harm. However, if you have a homemade PSU it might be better not to try anything at all until you know what you are doing. There is also very little that you could possibly break, except possibly for the meter itself, and I suggest you don't try using the 2000 mV or 200 mV DC settings. 20 V DC, or something like it, will be fine. Even 200 V DC or 600 V DC will work well enough for most things I imagine you want to do. Do make sure you plug the probes in correctly (unless they are connected permenently). The red lead must go to the red terminal on the meter or, if there is more than one, the one marked V. The black lead must be plugged into the black terminal, which may be marked COM. You can leave the probes plugged in the meter permanently, although you may need to move the red lead if ever you do current testng. When using the meter on a voltage setting, the probes are unpowered and you can touch them together and treat them like ordinary metal rods. Don't try sticking them into a mains socket or your toaster or anything like that. The only damage I can imagine you doing with them is if your PSU does not have short circuit protection. If this is the case, then you must take care not to allow a single probe to bridge across both positive and negative outputs. Touching one probe to the positive output and the other probe to the negative output is fine - it is what the meter is designed to do. Note that you have to touch both probes to the outputs (one to positive, the other to negative); touching just one will not give any reading. You asked about knowing which is the positive and which is the negative output. If, after turning on the PSU and touching one probe to one output and the other probe to the other output, you get a positive voltage reading on the meter, then the output connected to the red probe is positive. If the reading on the meter is negative, then the output connected to the red probe is negative (or zero, of you prefer). Apart from checking polarity, another common reason for using a voltmeter is to check for open circuits. Open circuits can be on either the positive or negative side, and one common approach, which might be what you saw in the video, is to measure the voltage close to the PSU or controller, where it should be fine. You then leave one probe connected at the PSU or controller, and then move the other probe progressively further away, ideally testing after each soldered joint or switch. If you get a reading on one side of a soldered joint but not on the other, then that is where the open circuit is. If you have tested all of the positive (or negative) circuit up to the track or whatever it is that does not work and not found a problem, then do the same with the other probe on the other circuit.

Because 0, like 00, is a scale-gauge combination. Or at least it was once, in dim and distant past. It now seems to be three scale-gauge combinations, with S7 adding a fourth. From my own enquiries into 7 mm modelling, one thing that I had settled for myself was to use 0-MF, with a track gauge of 31.5 mm. Perhaps I would need to join the 0MFA.

12 also appears to have GW two-hole chairs. I cannot quite work out where that window-edge is in relation to the train centrline. It doesn't look far enough to the left to be the centre pillar on a class 120 for example (and it looks too vertical for a GW railcar), but it looks a little too far to the left for most 3-window DMUs, so I wonder if it is an auto-coach, which appear to have had narrower middle windows (but I might well be wrong). I don't think the shadow in the four foot in 12 can be anything to do with the train. The sun is behind and a little to the left, meaning it would have to be something above the driver's head which wasn't on the opposite side. However, it is still very odd. Unless it is a colour light signal head (why there?). then for it to be an object further from the line it would appear to need to be very tall. I wonder if it is a lamp on an overbridge, although that would point to an almost excessive number of overbridges. I am no good at recognising signals, and can get nothing much from 15. The telegraph poles have an extra insulator on top which the poles in 12 appear not to have; I have no idea whether this detail is of any significance.

I do not model 0 gauge, but I had been toying with the idea over the past couple of years. Up till now, I had heard generally favorable reports of the G0G, as opposed to generally negative ones of the G1MRA which is also at the periphery of my interests, and would probably have joined had I decided to pursue 0 gauge modelling. However, reading this thread would certainly have put me off. Apart from the anecdotes from @SteveyDee68 and others, which might be attributable to a few individuals in isolated clubs/branches and not be reflective of the GoG as a whole, the idea of using a public forum for electioneering purposes seems objectionable to me. It would seem to me to be more honest to win your arguments from within (and in private), get yourselves elected, and then ask non-members what they would like to see, while at the same time saying what great things the G0G does, and keeping quiet about any divisions that might exist within the Guild.

Only for automatic signals, surely, which this was not.

It is entirely possible, I would have said. At Ladbroke Grove, low sun behind the driver reflecting off one of the yellow lenses of SN109 was conjectured as being a possible reason for the driver not seeing the illuminated red; I can easily imagine the sun's reflection being brighter than a signal lamp. The signal at Chalfont and Latimer (unless it has been replaeced in the last two years) has three aspects, so presumably this, too, has a yellow lens. There is a video of this route here, with the signal being passed at 2:18:

The signal had aleady been cleared for the Metropolitan train. I very much doubt the signaller is allowed to exercise any discretion at all following a SPAD. In any case, there is no mention of the signaller in the RAIB announcement, which suggests (although it is no more than a suggestion) that the Chiltern driver did not contact the signaller at all.

No, so I had less worry about people being on the line when propelling round blind curves. Most of the public foot crossings had good visibility, and most of the road crossings were gated/signalled. If necessary, we would stop short and a second person would check that a crossing was clear before waving the train across - trains were usually double-manned anyway. I was just trying to relate my own experience with industrial lines I had seen (I visited quite a few in the late 70s/early 80s, though almost all were standard gauge, with steam locomotives - hence my interest). I never actually came across propelling on industrial lines except in shunting, but there often seemed to be a lot more non-railway people about than is common on public railways, sometimes busily engaged in their own duties rather than paying attention to what trains were doing.

As a one-time driver on a narow-guage railway, I used to propel trains reasonably often. The wagons were generally well-maintained, the track was of an excellent standard and, being a "real" railway, we could rely on there not being people wondering about on the track, apart from those trained in looking and listening out for trains. As a result, we might on occasion propel reasonably long trains. However, most industrial premises aren't like that at all. Non-railway workers typically wander about all over the place, visibility is often restricted by buildings and obstacles, the trackwork might be poor, and so might the wagons. If you are planning a railway where propelling is a regular occurrence, I think you need to pay attention to lines of sight. Where it would be impossible for the driver to see if the line is clear, there would need to be some provision for safe walking routes, probably with fences to enforce them. This might not have been a legal requirement, but no manager would want their workers to be run over by a train because the driver could not see the workers were there, and the workers had no warning of the train's approach (propelled wagons can be very quiet). Apart from that, maintenance standards would probably have been adjusted to whatever the situation demanded, and if propelling 20 empty skips was the norm, then both the skips and the track would be maintained so that deralments did not happen too frequently. I might add, though, that propelling 20 empty skips sounds to me to be rather a precarious operation. If the line is uphill, then the locomotive would almost cetainly be at the bottom end.

I don't see how you can say that at all. Two trains each require to use the same piece of track at about the same time. One of them has to be signalled in front of the other, and the other one has to stop and wait. Stopping/holding one train is no safer or more dangerous than holding the other, and the whole of railway signalling in Britain for well over a century is based on this premise. Of course, a fast-moving train requires a considerable stopping distance, and a stationary train requires none, but this is built into the signalling and line speeds. It might be more expedient, in terms of the least delay to the least number of passengers, for a particular train to be given preference over the other, but this is not a safety consideration. In this case, the Chiltern train (presumably the 21:18 Aylessbury - Marylebone) would have been scheduled to stop at Chalfont and Latimer, a little over 900 metres beyond the signal, and the RAIB announcement implies that the Metropolitan train was ready to depart when the SPAD occurred. We aren't given any reason for the Metroplitan train having been given priority, but it is not an obviously wrong decision; in fact, it seems to be perfectly normal to me.

I am sure the quarry owner would have preferred to load aggregate directly into standard gauge main line wagons, but it is easy enough to imagine a situation where this was not possible. Perhaps the terrain was too difficult, or the landowner wouldn't allow a route that was straght enough for standard gauge, Perhaps the volumes weren't economic for standard gauge, or the railway company did not like working their own trains over private feeder lines, and the quarry owner felt that operation of their own standard gauge branch line would be too expensive. The existence of railways like Leighton Buzard, even though this was a common feeder for several quarry companies, shows that the scenario entirely plausible.

I hadn't spotted the ground frames. I imagine the three levers are what had been 6 and 9, and a single lever for the two FPLs, normal in the locked position. The north platfform has now gained a trap, since with no signalman it now needs to be isolated from the running line. The locking bars have been removed (There appears to be a hint of a locking bar (10) at 1:49 in the first video).

Following Martin's excellent find, I see there is another video, showing a different method of carrying out the shunt. No signals are visible, nor is the signabbox, but since neither locomotive nor carriages appear to have reached signal 13, any signals (if there were any) must have been given by hand by the signalman.

Ah, I now see why you wrote this; I hadn't noticed the two lines pointing to the signal arms. It looks as if the draughtsman originally drew each signal mounted on its own post, but then did not change the position lines when he drew a bracket signal. I don't recall seeing lines on a signalling diagram showing which arm is for which road, but there should be a line on the diagram showing where the post is located. I suppose this depends on how the move was carried out. If the loco just moved out of the way into the other platform, then I doubt they would have been locked, unless the signalman particularly wanted to check that the locomotive was clear of the points by making use of the locking bar worked from the FPL lever. I suppose the signalman would have given hand signals for the movements from the signalbox. However, if the locomotive went to the engine shed or to take water, then I imagine that 12 or 13 would have been cleared for the gravity shunt, and presumably later on for the locomotive, even though the line was occupied, since no shunting signal is provided for that purpose. [Edit: you can clearly see signal 13 cleared for the light engine movement in the video below] You might need someone with local knowledge to discover whether or not the starter would have been cleared for backing a train out of the platform. Banff would probably need permission from Tillynaught for the move, so it ought to have been possible to get a release if using the signal was allowed.

An American businessman arranges for bathroom furniture to be deiliverd to his Scottish holiday home. He has some problems with the shipping company. This is a truly delightful film and I am sorry I have had to make it sound so dull.

My guess is that the ferry is heading to the left, and that it has a straight stem bow and counter stern. This might mean that it is sailing from Folkestone to Calais of further east, or it is sailing from Boulogne to Dover (if Dover shed is where I think it is).

I had wondered that, but if that were the case I expected to see 12 just requiring 3 & 10 and 13 just requiring 10 (matching the actual interlocking). I also wondered if it was to avoid pull-betweens on 5 and 8, but it looks to me to be interlocked the wrong way round to do this. Of course, the signalman could avoid a pull-between by setting 4 normal before pulling 5, and 7 normal before pulling 8 (both levers will be free), but he is not compelled to do so. I have no idea what is considered good (or even acceptable) practice in this regard.