Martin Shaw

Chris I feel your setting yourself up for a hard task if you go down the route of using ground frames to which you want to fit lever locks and circuit controllers. The space requirement is I think going to defeat you. Basically the choice likely available is either Westinghouse D series or SGE, both of which are large and whilst having the capacity for a circuit controller, aren't designed for external use. The other option is baby locks to which you would also need other circuit controllers. It's an awful lot to cram onto the back of a GF and Stevens knee frames were designed before electrickery anyway. I don't say it can't be done, but I wouldn't start from here. Ian S&T is no different from any other part of the many systems that make up an operating railway, they all have to be maintained to a standard. I'm all in favour of simple and safe, and S&T installations on heritage railways are, by virtue of the equipment being a known and proven entity, and the installation being designed to well documented principles and standards. The HMRI have no inspection per se these days anyway, it's done by Independent Competent Persons who are engaged as part of the design process, nor is it technically difficult, so absolutely no reason to shy away from it if that is the railways choice. Of course not having any signalling is also a wholly valid choice but it does bring its own limitations. Regards Martin

Jim has made the point I would have as well. It's worth noting that there were several classes of superheated slide valve engines that seemed to work ok. The advantage of piston valves is that the load on the valve against the ports is not a direct function of steam pressure which means the frictional losses are not so great, live and exhaust steam distribution tends to be better as well. Regards Martin

OK folks, I spent half an hour this morning oiling up an Austerity, the right crank leads the left crank by 90 deg when going forward. The wheel pins for the coupling rods are at 180 deg relative to the crank on the same side of the engine. The crankpin throw is 13", the coupling rod throw about 10". The eccentric throw is I would guess about 4", but to be honest this last is a bit of a guess. Regards Martin

Mark You could try Douglas Blades of Ardrossan, I bought quite a few volumes from him earlier this year, and he had a lot more. Regards Martin

Nick In answer to your question, absolutely nothing, although to be wholly fair to signalmen throughout history I can only think of a small handful of incidents where signalmen have bent or broken rules that resulted in loss of life, and in truth really only one where the signalman possibly had malice aforethought. There was and possibly still is a regulation such that signals cleared for routes with points in them should not be returned to danger until the train has cleared the points, so holding the locking. Treadles and backlocks, not really. Martin

Nick If you compare your two linked photos, the earlier one shows a vaguely triangular device to the left of the points, this is a hook selector used to determine which signal of two worked from one lever would clear as determined by the lay of the points. In the later pic this has disappeared and replaced by a weighted detector, used to ensure the detector slide fully clears the notch in the stretcher. I have found on David Hey's site a picture taken in the opposite direction for the platforms and the running shunt has been removed, and with that gone the locking bar is pretty much redundant, so likely BR took it away. Track circuits on a secondary byway are exceptionally unlikely, to a point I can almost say definitely not. Hope this helps. Regards Martin

Mike Thanks for your thoughts, in essence though they are one and the same thing, I can't imagine a situation where a running shunt didn't precede the runnng signal in the locking, and if not an afterthought, would most likely lock the points and FPL as well, as well as holding the route. I do recognise that a shunt signal might be provided purely for route holding purposes, but certainly from an SR perspective it would be treated no differently. I suspect this is getting to a point of semantics rather than anything else. I note your comment in respect of the WR, no surprise really. Regards Martin

With respect Becasse, as I pointed out in my earlier post, Wagstaff recorded 7 pull existing in 1920, which is certainly before Southern days. He may well have been wrong, but since this is the primary evidence of it's existence, I would prefer something more substantial to deny it. Mike, would you care to differentiate between a running shunt and it's additional use for route holding. Regards martin

Hi Guys Only just picked up this thread. I've had a look in Wagstaff and his diagram for Hayling Island shows two separate posts for the home signals with the advance starter on one of them. The distant signal is shown as fixed and 1 is the FPL on 6 points. The diagram is dated 1920 so predates yellowisation of the distant signal. I think, as others have commented, lever 4 originally worked both FPLs and 1 would/might have worked the distant. I think that the arrangement of the homes/advanced starter may well have been the original installation and it has been incorrectly perpetuated in drawings ever since. It is likely that the LB&SCR renewed the signals on the line, perhaps in the 1890's or thereabouts, and is apparent that separate home and advancd starting signals were provided by then. I have a book titled "Branch Lines of the Southern Railway" by Reeve and Hawkins published by Wild Swan in 1980, which helpfully has a section on the Hayling Railway which includes 3 very useful photos of signals. A front and rear view of the down home signals, a bog standard Brighton equal doll with absolutely no sign of a former up advanced starting signal ever having been there, and more importantly a front view of the advanced starting signal, again standard Brighton desing but somewhat short in stature. All the posts of theses signals have been sistered which suggest the posts themselves were badly rotted and I would suggest the renewals by rail built versions was for no other reason than life expiry of the wooden ones. 7 pull existed in 1920 and probably from whenever the line had its signals renewed, it provides a measure of route holding, both the Brighton and the Southern were quite fond of this arrangement. I was bemused by Becasse's comment about the use of tickets being unusual, there are plenty of photos showing two trains at Hayling Island, at least one of them must have got there by using a ticket, which occured on a daily basis, at least during the summer timetable. I can also confirm that there was no connection between the block or staff and signals. It relied totally on the integrity of the signalmen and drivers obeying the rules. Hope this helpfully supplements others comments. Regards Martin

Bit of a sweeping statement, which really isn't correct. The LBSC certainly used them sparingly where they had usually run out of spare levers, but they weren't run of the mill as the Midland used them. I have copies of the Wagstaff drawings which are dated 1920 and at that time Cranleigh had an EFPL, lever 9 which had by the time of Pryer become the FPL , the switches became 10 which was henceforth a crossover. Baynards didn't have any EFPL's but a slightly odd 2 lever GF which worked the loop points and FPL furthest from the box. The points were bolted normal and reverse by two of the box levers which released the relevant signals. It's interesting to note that the section from Baynards to Rudgwick was worked by train staff and ticket with Harpers instrument, disitinctly different from the Webb and Thompson ETS one might associate with LBSC single lines. Given that Pryer dates the Baynards drawing as 1935 it's reasonable to assume that the Cranleigh drawing is similar. It was I think 1925 when the limit for mechanically worked points was extended to 350 yards. The Brighton were quite fond of floating wheel detectors where selected functions were required from the lay of points usually, but I see no reason why an FPL should be inherently different, so two signals and an FPL from one lever is quite possible if a bit of a maintenance liability. Regards Martin

Hi DMUdriver Notwithstanding all the interesting diversionary conversation, the release lever on the ground frame should be blue over brown. It may also work an FPL if required in which case it would be full length, or if a separate FPL lever is installed, certainly current practice, the release lever would be cut down, whether electrically or key released. BY the 70's the painting colours for levers was a UK wide standard although plenty of earlier examples existed to contradict it. Regards Martin

Richie I've found a drawing of the AEI/GEC version. This came in a number of variants but the most common single unit is 16.75" wide by 20.25"high and 6.25" deep. The hood protrudes 10.5" at the top and tapers to nothing 19" from the top. This for a single unit, the double unit is obviously enough twice as wide, there were also double sided versions and they could all be pole and gantry mounted. Hope this helps. I would imagine that Westinghouse and SGE units would be similarly dimensioned. Regards Martin

Probably it was likely driven by the overall cost of the scheme, rather than a specific element appearing to be a significant addition. If you've ever had to deal with costing alterations on BR, the obvious is not necessarily the best, I remember such occasions rather too well. Regards Martin

A thought if I may, the signalling at Crianlarich was significantly modified upon closure of the C&O to the east in 1965, and the section westwards extended to Dalmally. To allow for free acceptance when a train was accepted from Tyndrum Upper an additional outer home signal was provided which is the signal in Beast's pic. Electric token working was still in use in 1981 and I believe the situation with the Rule 55 exemption on the diagram was that there was a TC there before and when the diagram was altered the diamond removal was overlooked, or, the diagram had an addition that it didn't warrant. Regards Martin

Andy Thankfully nowhere near as large, only 496 pages, but still around £85 to purchase. Britain is by American standards very small and has had the benfit of a centralised electrical generation and distribution system which has resulted in a countrywide standardised approach to electrical installations. I'm not for one moment suggesting that it is inherently any better that way, just the way it developed. In my opinion the ring final circuit is an historical throwback that should be outlawed, but we seem wedded to it. Regards Martin

Ray Errm yes I'm afraid it has, four times in fact, 3 amendments to BS7671:2008 and BS7671:2018, although most of the variations are relating to zone sizes or RCD protection of final circuits, and are not retrospective. It is worth mentioning that part P of the building regulations only apply in England and Wales, Scotland sensibly does it differently. Regards Martin

Your quite right, it hasn't taught me any respect for someone who despite many posts that they are wrong, continues to argue to the contrary. I have read your last post, I would suggest you speak with Charles Hudson MBE who can possibly elucidate you. In respect of your use of a track circuit example, of course when a train occupies it, the voltage drops and the current rises, because quite simply the resistance has fallen, it's no more magical than that, if you can't grasp this basic principle then there really isn't any point. Stop fighting it. Best wishes Martin

I have read this thread with some interest, and after 47 years as a professional electrical engineer one of the few things I definitely know is Ohm's law, and it's application in any electrical circuit will always have the same impact, as many others have already made plain. However counter to this is the proffered argument by the Sussex flat earth society which goes like this. If you take a 100% efficient electrical device that can give a 1000w of output work, you have by virtue of Newton's laws to feed it 1000w of electrical energy that could well be in the form of 10v at 100A. If you halve the supply voltage to 5 and at that PD the device will still give 1000w ouptut then the current will indeed rise to 200A, this is of course nothing to do with Ohm's law, and everything to do with a change in how the device works which electric heaters can't do. On a serious note the issue isn't moulded plugs per se but the relationship between the plug pin and the wiping spring contacts in the socket, these can become corroded in hostile environments which causes a high resistance and localised heating. As the springs heat they lose temper which worsens the state of affairs increasing the heating which manifests itself in the plug. In any case both the plug and socket should be changed as both present a fire risk which may ignite before a 13A fuse blows, as well as personal hazard. Whilst I recognise that BS1361 permits a maximum rating for a socket outlet of 13A I personally wouldn't want to use a device at that current for a prolonged period. In all electrical matters assume it's dangerous and make your own safety the highest priority. Regards Martin

A long time ago, autumn 1972 aged 18, I joined the LMR S&T dept. My second day on the railway involved going to Watford Junc with a senior colleague to look at the two control trains stored in the carriage shed, adjacent to the St Albans branch. They were I think formed as 3 car sets, but of what stock I have no idea. To my untutored eye the equipment looked way beyond use and I do agree with an earlier poster, that the visit was likely to see if anything was worth recovering for re-use. The most striking memory though was of the carriage shed foreman, old enough to be my grandfather, addressing me as sir. Happy days. Regards Martin

Was it really 1976 Stationmaster, hardly seems like yesterday. There was I think a general pay review of salaried staff at that time, which generally meant that everyone went up a grade. At that time I wasn't on the top rate for STOs so I stayed as I was. As a result all my colleagues who had been STOs became MS1s and lost out significantly, not only that as well as my own overtime I picked up the odd hours they didn't want cos they weren't going to work for nothing, I was taking home at least as much as my MS2 boss. Martin

I'm a bit late to this thread, but interesting nonetheless as I grew up in Orpington. I have a BR-SR locomotive route availability dated 1-12-62. Regarding the Tonbridge to Bopeep Jn line, the following classes were barred, N (allowed between Tonbridge and Grove Jn), U, W, E2, E6, K, G16, H16, MN, N15, O2, S15, V 8w tenders, WC original and rebuilt, Z, All Diesel Electric locos except narrow body Cromptons, All Diesel Hydraulic locos,BR Stds Cl4 4-6-0 and bigger, most of the smaller ones had major restrictions, all LM region locos, B1, WD 2-8-0. Actually it would have been quicker ti list what was allowed. Regards Martin

Kevin Yeadon Vol 38 has a good photo of 1882, probably at Stratford, but certainly London. The engine went to Stratford on 12th Jan 1939. Regards Martin

Simon As a former S&T bod the answer is that the signal engineer would do absolutely nothing other than say your siding is too short. In the real world any vehicle that coudn't be parked with adequate sighting of the signal would be banned from using it. Unfortunately there is no realistic getout, don't seem to be any traps either. Regards Martin

Hi St Enodoc You and I probably know each other, I was often signalman at Sheffield Park at that time. I remember well bell codes 5-2, release staff for shunting, and 2-5 shunt withdrawn. This was I feel prior to the installation of the outer home and advance started at SP. No doubt If I ploughed through BNews for the time I could date the events. The pull off down the Newick spur was to retain some semblance of a timetable on summer sundays because you couldn't round via the single line. It was a long time ago. Regards Martin

Jim It's Stirling Middle, I haven't been there for a while so the current position is probably a bit different., there has been some rationalisation. The distant under SM47 is for Stirling North. The three way bracket is as you surmise correctly, The off arm at one time had a distant arm for Stirling South, long gone, although I agree if you don't know the layout the capacity to confuse is great Regards Martin