jamespetts

This is a fascinating topic and I have just spent a considerable time reading all the posts. I shall very much look forward to the video. Sadly, it seems as though your book has sold out.

Gosh, how have I not found this thread until now? I am very much in favour of realistic signalling control for model railway layouts, and am currently building my own layout along similar lines (albeit with TrainController rather than JMRI). I shall very much look forward to seeing progress on this layout and perhaps seeing it at an exhibition one day.

My transfers arrived in the post to-day - excellent service!

Do you mean a virtual extension to a real layout? This is certainly possible - I already have this in progress on my layout, albeit with modern signalling.

I did look into using JMRI, but found that it lacked many of the necessary abstractions (such as a schedule) necessary for full automation without having in effect to write a very substantial piece of software from the ground up in JMRI's scripting language, which would be very vulnerable to breaking with any major update to JMRI. Edit: Incidentally, I should also note that iTrain lacks variables, which means that one cannot do the same thing as I described above using TrainController.

Excellent - have just ordered a set.

The basic method for having trains running automatically with manual signalling is described in the TrainController manual at pages 360-1. In essence, what you need to do is lock the exits of the blocks that immediately precede on the train's path the blocks that you want to control as a signaller, and then set up a route manually in the software that is one of the routes that the train, under automatic control, is programmed to be able to take. If you configure the system to unlock the block at the same time as a route is set, because TrainController will always prefer the route that has already been set, this is the route that will be taken. I have so far implemented this successfully for a part of my layout (and have only done a part so far as I have only recently finished wiring it and not yet finished adding the hardware addresses into the software). However, my layout is set in the 1980s using modern signalling systems with computerised NX ("eNtry eXit") control, which does work more easily with TrainController's systems. I have not tested this with a functional representation of mechanical signalling (or a form of signalling controlled by individual levers rather than route setting), but I believe that it should in principle be possible. What you would do in such a case is have levers for the individual turnouts in a straightforward way, and have all the route setting logic in the lever controlling the signal that you have to pull off for the train to be given authority to proceed. Imagine for these purposes a simple double junction: a train on the diverging route may be signalled either to point A or point B or may be held at the signal. The block immediately preceding the signal controlling the double junction would be locked (for more sophistication, you could have a switch, either in hardware or software, to unlock this if you want fully automatic operation for any reason). A train would therefore be held at the stop marker in the block, which you would set up to be at a realistic distance from the signal controlling the block. You could then pull the levers for setting the route either to A or B. In a semaphore signalling world, you would have two different signal arms, one for route A and one for route B. You could set up logic so that you can only pull off the route B arm if the points are set for route B, the arm for route A is on, and the track is unoccupied. Pulling the route B arm could then trigger (1) the setting of a route through the junction to the block beyond for route B; (2) the movement of the signal itself; and (3) the unlocking of the block behind the signal. Depending on how you had set up the train's schedule (i.e., whether it is allowed to take both route or only one), setting the wrong route would either allow the train to take the wrong route, or the train would simply refuse to move even with a clear signal if the wrong route had been set. You would then do the same for route A, and set up the block behind the signal on the diverging route to re-lock automatically (if your "full automation" switch is not set to on) as soon as the block switches from being occupied to unoccupied. You would also do the same on the converging routes, save that there is only one route through the junction for these routes. This system would simulate a mechanical signalbox with track circuits in that there is an interlock to track occupancy built-in. I am sure that it would be possible to simulate the operation without track circuits, probably by using fewer occupancy sensors, giving a realistic possibility of collision should the signaller get things wrong! Communication with neighbouring signal-boxes is more complex; I have not done this yet, but I believe that this is likely to be possible. What you would do is set up logic to simulate the entry of the train in question to the next signalbox down the line. Imagine again our double junction and a train approaching on the diverging line, and imagine a layout with just the double junction and fiddle yards on the plain track beyond this section. For each train movement between the fiddle yard and the diverging line, you would set up a macro triggered by a timetable event (or any other kind of event, such as a button press) that would trigger a sequence of events when it is time for a train to approach. You would set a variable representing occupancy of the preceding section of track by a train, would prevent any other train from being offered until the line had cleared. You would then set a sound to play representing a bell code for the class of train in question (using variables and flow control logic; you would assign a variable to the train in the macro that starts it defining its class, e.g., ordinary passenger). This would just be a recording of a sound, either from a real signalbox, or a recording that you could put together from a bell that you can find somewhere. You need then to set up a button in TrainController to constitute the acceptance of a train from the signalbox in rear. The one thing that would be very difficult to do (not impossible by using an Arduino or similar - but would require a lot of work) is make TrainController recognise actual timed bell codes, so that pressing a button in a tap-tap-wait-tap sequence means one thing and pressing tap-wait-tap-tap means something else. So, unless you could set up an Arduino or similar to encode these signals, you would have to compromise on the interface a little, and just have different buttons to represent sending different bell codes to different boxes - but you could make up for it by having the system play a recording of the right pattern of taps when you do this. On acceptance, a macro would run with a timer representing the time that it takes for the train to pass out of the section in rear and up to your outer home (if you have one), or up to the point when the train would be ready to enter the scenic section. Assuming the simpler case with no outer home, the expiry of the timer would trigger the start of a "schedule" on the actual layout, causing the train physically to enter the scenic section and either wait behind the signal if at danger or proceed if it is at clear. With a little more sophistication, you could also set it up so that, if you had pulled off your distant in time, the train would arrive into your section much faster than if you had not. Some care would need to be taken to ensure that trains scheduled to enter the section in rear but which cannot because that section is occupied do not become lost: you would probably have to program a queue system or similar. Note that you cannot rely on macros running with timers and repeats, etc. to store information, as macros are terminated and the data in them lost whenever the system is paused or TrainController exits, so you will need to use macros that run periodically and check global variables that have a persistent state. So, as indicated, this is possible, but it takes quite a bit of programming work in TrainController as there are no built-in systems set up to do this easily.

This is possible with TrainController, albeit with some careful configuration.

I think that I shall be after some transfers to convert the sleeper carriages into Executive livery, too. Here is a(n unembeddable) image from Flickr showing one of these sleeper carriages in 1988 at Oxford, definitely without a hyphen in "InterCity".

I have tried resistive paint in the past on N gauge axles, but found that it was not reliable: as the paint dried, I think, it would crack and form breaks in the conductivity. I wonder whether the particular type of resistive paint makes a difference?

One thing to bear in mind: P4 requires generous curve radii - much more generous than 00. An L shaped layout inherently requires a 90 degree bend. Achieving this in P4 is likely to require much (and possibly all) of the length of the layout (unless the room is very large indeed) to be taken up with the curve. For this reason, fine scale layouts generally tend to be end to end or gently curving ovals. Check the curve radii and your available space mathematically to see what will work for you.

Gosh - some of those wires are thicker than mains wiring! That is what you need, I suppose, for a huge length without voltage drop and with 0 gauge levels of current draw.

I see that discussion of this issue is now being censored: a reply that I posted to this thread recommending uBlock Origin was deleted and the topic locked without public explanation.

Very interesting - there is much to be said for this approach. May I suggest that it would be helpful to have more detailed instructions about how and where to solder the droppers, especially if you go over to an all rail system? I have had problems on the code 40 N gauge products that I have had working out how best to deal with the very short length of rails immediately beyond the cast crossings; the solution that I adopted, making them longer than the ends of the bases, often a continuation of the rail from the preceding straight section of track, caused problems in that the wheels would cause shorts on these where they converged. Cutting them back so as not to converge so closely then resulted in large gaps. A better solution electrically would be to make the whole of the crossing and the short parts of the rails that emanate from the crossing to the end of the turnout section all connected to the crossing polarity switch, but, in the current design, this requires soldering droppers to two very short pieces of rail, and it is not at all clear how to do this effectively. An all rail solution would of course need droppers soldering to such short sections of track in any event, so having detailed instructions on how to hold these in place while soldering and how to do it without melting the chairs, etc., would be most welcome. Since I am planning on possibly building some more N gauge layouts in the future, these developments are of interest.

Interesting. May I ask whether the code 40 N gauge products will also change over to "all rail" in due course?

1989, I believe.

The larger producers of browsers (Google especially, but also Apple, who wish to compete with Google for advertising revenue) have a fundamental conflict of interest leading them maliciously to interfere with advertisement blocking functionality even though it is in the interests of browser users to permit fully functional advertisement blocking. Do not trust the excuses given by these organisations for the abusive behaviour in restricting advertising blockers. Instead, use Firefox, a browser produced by an organisation dedicated to internet freedom. In reality, there were internet forums run by enthusiasts long before paid advertising on forums was a viable business model. If an advertising backed model were to become unviable in the future because of increased use of advertisement blockers, forums would not go away: amateur run forums would replace commercially run forums. People would probably have to host their own images (e.g. on the free web space normally provided by ISPs) as amateur forums would be unlikely to be able to pay for mass image hosting, but there would be no incentive for those who run forums to make the experience for those who do not pay as unpleasant as possible to coerce them into paying to upgrade. Likewise for video hosting: if YouTube were to become unprofitable overnight, PeerTube would take its place. There would be no shortage of video hosting capacity nor people who make videos because they enjoy it and want to share the things that they love. Thus, a choice about whether to use advertisement blocking software is not just about whether to "support" things that you want to see. It is a choice about what sort of economic model that you think is preferable for hobby content on the internet: one dominated by large commercial concerns, or a decentralised, largely amateur based economy. I know what I prefer.

I have no idea why anybody would ever not use one.

A very useful article. The trouble with the Mill Hill/Finchley freight services seems to be that they were mainly handled by ex-LNER N2 locomotives, which are not available in N unless one counts a Langley white metal kit that requires a Poole era Farish chassis to work and is thus not up to modern standards. If J50s were used, then this would have been more interesting given Sonic's recent announcement of this class.

Sadly unembeddable, but there is also this photograph of 33008 hauling a 1938 stock train (with match wagon between locomotive and train and brake van at the end) from West Ruislip to Eastleigh ready for rebuilding into class 483s for the Isle of Wight.

Interesting, thank you. This source about the signal cabin at Morden suggests that the peak time frequency there was a train every 1 1/2 minutes: that is 40 trains per hour, suggesting that the original claculation of 42 trains per hour from the 1957 timetable was not far off.

Following the Revolution Trains announcement of N gauge 1938 stock, I wonder whether there might be merit in designing an N gauge Underground layout instead, which might well fit in the space more easily. A brief sketch of Morden, showing the same baseboard outlines as for the Aldgate plan is reproduced below. As can be seen, there would be much spare space if this plan were used. I am not entirely sure which is superior for operational interest; the Morden layout would have more movements off peak*, but the Aldgate layout would have more varied traffic in peak time. The Aldgate layout would allow a greater variety of rolling stock - but the Morden layout would allow a little 009 layout to fit in the spare space and have a whole different sort of variety. Indeed, both the Morden layout and an 009 layout might be portable rather than fixed. I should rather not have to decide any time soon, but the Revolution Trains units are all crowdfunded and would require pre-ordering, so planning some way in advance would be necessary. * At least in 1957, Aldgate would have one circle line train each way and one Hammersmith & City/Metropolitan train each way every 7 1/2 minutes off peak, that is, 32 trains per hour. The timetable for Morden is oddly difficult to interpret, but an off peak interval of 3 1/2 minutes is given for the via Charing Cross route and 2 1/2 minutes for the via Bank route, giving 41 trains per hour. However, the timetable is ambiguous, and, on another reading, there is only one train via Charing Cross every 5 minutes and one train via Bank every 10 minutes off peak, giving only 18 trains per hour.

I refer to Nigel's response above, and also to the experimental demonstration in the video of the build-up of insulating oxide deposits on track. It is factually inaccurate to state that stalling can only ever be an issue on improperly laid track.

May I suggest watching the video for an experimental demonstration of the accumulation of insulating oxide deposits on track? Well laid track can certainly reduce stalling compared with poorly laid track, but cannot eliminate it.

I normally use the unit's TOPS number as shown on the front of the unit, minus the letter. So, for example, this unit: Graham Farish class 101 by James Petts, on Flickr would be 840; this unit: Dapol class 121 by James Petts, on Flickr 124; this unit: Dapol class 121 by James Petts, on Flickr 131; this unit: Express train meets local by James Petts, on Flickr 204; this unit: Graham Farish class 101 by James Petts, on Flickr 207; and this unit Dapol Class 122 by James Petts, on Flickr 1. (As seen here, it did wear just "01" as a number at one point). For units that carry the full three digit TOPS class as part of their number, such as the class 150 (I seem not to have any pictures of my class 150), 1 + the three digit number, e.g., 1001. My general numbering scheme where the displayed number includes the class number is to take the first digit of the class plus the three unique digits of the locomotive/unit.