PSi

Dear Moderators, The green banner mentioning about the ongoing resoration of lost pictures has gone. Have you given up? Should those still having the original pictures replace them now? I just could not fully understand what was said on message dated Posted "Tuesday at 15:52" [Why not say 26.5.2022 at 15:52?] from "AY Mod". Should one touch old messages or not? Please tell in plain English so that us foreigners can also figure out what to do.... Also please tell us why RMWeb removes all EXIF etc data from the jpg images — including the Copyright field...

This is a good lesson to all of us relying on single drive at home or a cloud service provider actually making data backups. I've heard of a urban legend of a service provider that in their customer contracts agreed to rediculously low penalties in case their backups failed. The story said that the company did not bother to take any proper backups as the cost of proper backing up was higher than paying for the data lost. When the server failed it turned out the company had not even attempted to make any backups whatsoever. I may have to regret saying this but: I hope the avatars lost were the moving gif type things that kept on flashing at the side of the screen while trying to read the messages. Due to design it is impossible to reduce the browser screen or zoom in the view to push the left hand column in to wings.

May I still return to 'Ashbourne (Midland)': Do you recall what was the lengh of your headshunt and how long a rake of coaches/wagons standing at platform track could be run around? /pekka

Thanks — Jim! If this is the case, I would have thought that the two extra "full feature" sets of contact wire and catenary wire were joined and be replaced with a single cable, supported with extra cantilever arms and be anchored at next possible location, and not being used as double or triple contact and catenary system. As the system is not tensioned with weights or springs, braking of a single contact or catenary wire will probably not cause sudden oscillating movement of the combined system. I wonder how the lower voltage (1500V etc) double contact wire systems are terminated: Are the contact wires just considered as "two strands of a cable"... Thankyou for quick and informative reply!

At a Finnish rail related site "vaunut.org" there is a photo taken from Crewe station platform about the catenary wires of the station. It appears that there are three parallel catenary and contact wires running on common cantilever arm and registration arm: http://vaunut.org/kuva/141457 There seems to be two parallel wires at least on platform 5: https://upload.wikimedia.org/wikipedia/commons/c/ca/Crewe_railway_station_MMB_02_350259.jpg Why two/three parallel wires? Why all are supproted on common supports so that they may not be individually tensioned? I have not found any technical reason or explanation for this. Where I could find a reason behind this? To my understanding, the vertical control of the contact wire is by cantilever arm or swivel arm supporting the catenary, and contact wire being supported from catenary with droppers. I trust that registration arms are only used to guide the contact wire horisontally. All reference I've seen so far suggests that parallel wires need their own cantilever arm to individually compensate the lengthwise movement due to expansion and tension. What I've seen is, that crossover wires have separate cantiliver arms (swing arms) and registration arms attached to it to make them mecanically independent, and to allow individual tensioning and lengthwise movement. The exception only being the anchoring cables attached to cantilever / swivel arm at the middle of long catenary wire. Do you know of any freely available matrial on the Internet that I could see about having parallel wires in same cantilever and/or registration arm in UK? The stuff I've found: "Network Rail: A Guide to Overhead Electrification", February 2015 Rev 10 by Alan Baxter, https://www.bathnes.gov.uk/sites/default/files/sitedocuments/Planning-and-Building-Control/Planning/nr_a_guide_to_overhead_electrification.pdf and "Overhead line electrification for railways", 4th edition 2016 by Garry Keenor, https://www.railwaysarchive.co.uk/ocs4rail/download/Overhead-Line-Electrification-for-Railways-4th-edition.pdf have no mention about having multiple catenary wires supported by common cantilever or multiple contact wires guided with common registration arm. A bit of googling (Google map googling) reveals that it appears that Crewe has "double wires" or "parallel wires" at least on tracks at Platform 5 and platform 6: https://goo.gl/maps/aevtpnj2RnT46ASXA but not at platform 11. The catenary on above photo is supported with single cantilever arm and the registration arm is connected to one contact wire and the parallel contact wires are connected to each other with some sort of links. The parallel catenary and contact wires cannot independently move lengthwise, so they must act as "strands of a common cable" or something. I still cannot find description telling why 25 kV line would needs doubled or tripled catenary and contact wires, and how the three wires are individually tensioned... E-mail to nationalrail.co.uk and avantiwestcoast.co.uk (on June 2021) has not come up with any help yet. pekka

Thanks, Nick! Having finally given up hope of having a large dream layout I've tried to scale down 'Ashbourne Midland' into N scale as a base of a layout one might get finished. Unfortunately all of my unfinished dream layout turnouts are long ones, so more compression is needed

Nick, On BRM January 2018 You mentioned that your trackwork is Peco Code 75. Are you using Long, Medium or Short turnouts? pekka

Again, some old shots, this time Copenhagen Fields. Sorry for lousy quality. pekka

Looking back — perhaps slightly off topic — some shots of the predecessor of Copenhagen Fields: Chiltern Green & Luton Hoo! These shots were taken at December 1981, roughly 40 years ago. The slides were shot on daylight film, quite under-exposed, now heavily adjusted to get something out of them. Sorry for the colours! pekka

I had been in correspondence with John Geach (snail mail) and luckily got myself invited to see Keen House during our visit to UK to see our relatives. This was my first ever visit to Keen House. I was in seventh heaven! Under construction were "Chiltern Green & Luton Hoo" and "Thame". The photo SGF mentioned seems to show some sections of "New Annington"? If my memory serves me right — and my command of English was good enough — I recall someone mention that the "Thame" canopy slates were cut from wine bottle caps, all wine drunk by one member of the club :)

Thanks! Looking forward to seeing the layout finished -- something I've always failed to accomplish pekka

My photos of Thame taken at the Model Railway Club around Xmas 1981 pekka

Slightly off topic: The term foam board is often mentioned at RMweb. What brand are You using? The thread "Remove paper from foam board" introduced several brand names: Westfoam, Peterboro and Kapa. It appears that different brands use different types of glue for laminating the paper/card on foam core. if foam board is used as track foundation, how does the paper/cardboard lamination stay on the foam core if the ballast is glued by liberally soaking it with diluted PVA glue, acrylic matte medium or Woodland Scenics' Scenic Cement? Was it necessary to coat the paper/card to make it waterproof? [I'm more of an armchair modeller now, with no experience of today's materials or techniques. If this is not the correct forum, then please move... /PSi] pekka

Ah! Thanks a lot! Yes, it was the sound of resetting of the overload trip that I faintly recalled. You made my day pekka

Please do! pekka

This is rather an odd question, but still: My relatives used to have a lot of Hornby Dublo stuff, and when visiting them in the late 60's I was allowed to assemble a huge layout on the floor of their hall. Thy had two locos, the other was A4 Mallard, I cannot recall the model of the other loco. The locos suffered from rather rough handling and some of the valve gear was in a state that caused the locos to occasionally jam. The controller was a Hornby Dublo A3 controller. When the loco jammed, or I accelerated the train too fast, the overload tripped inside the A3 controller. The overload trip was reset when the speed controller was set back to zero. The sound of the tripping and releasing of the overload trip was interesting, but this being some 50 years ago... I wonder if any RMweb readers has still got a Hornby Dublo A3 controller in working order and could record the sound of the overload tripping and releasing, or if someone knows of a YouTube video where the overload trip could still be heard. pekka

From the wikipedia (about standard 4 mm banana plug): https://en.wikipedia.org/wiki/Banana_connector#History "-- The pin's diameter is nominally 4 millimetres (3⁄16 in). The pin has one or more lengthwise springs that bulge outwards slightly, giving the appearance of a banana [bunch]. --" pekka

2.6 mm banana plugs or 'Marklin' plugs. E.g. here: https://www.conrad.com/search?search=2.6%20mm%20jack%20plugs&searchType=regular (I'm sure a UK suppliers also exits) pekka

This is not strictly simple, needs common anode signal heads, but the component count is still rather small, and there are no processors or fancy digital buses, just one IC (quad operational amplifier) for four LED lamps. Cut the wire leading from (grounding) switch to the LED's curent limiting resistor and connect the circuit points (A) and (B) in between: I drew this in 2006 and had it at Tapiola Parish Model Railway Club's web site's page https://taprk.org/eng/project/semaphore/ for 14 years. After showing this at MERG BBS i was noted that the schematic had power pins of the OpAmp reversed , This is the fixed one! The idea is that when swiching on a LED, first nothing happens, and then, after about half a second the LED starts to brighten, and is fully lit at one second after being switched on. When switched off, the LED becomes dark within half a second. So, if one switches off one LED and switches on another, the first one will go dark before the second one will start to brghten up, thus giving the illusion of "changing aspect through dark". I wonder if this is the desired action... True, may be done with much less components using a processor following x^3 curve... pekka

A link -- please ? pekka

John, you are preytty good with this – aren't you Excellent! Looking at this now, the system has departed from the NX into something different but rather elegant! If I should do this for myself I'd rather have the toggle switch between buttons A and B to select the "end". I do hope the original writer – Spikey – has enjoyed this as much as I have! pekka

Hmm... I don't think so.... I know I should have marked the coils to follow the track letters, but being lazy I left the coil letters as they were: coil "a" leads to track "B" and coil "b" leads to track "A". Sorry! I know now that I should not have done it the way I did. If I may borrow the words of Spike Milligan: "It's all rather confusing, really!" Suzie: Yes — but I would so much hate to add buttons in between and ruin the NX idea pekka

John ks — thanks for the addition of the missing diode! I did have a strong feeling that I missed something Are you quite sure about the swapping of the point motor V3a/b? I have my suspicions... Replacing buttons A and B with a toggle switch is a good addition, especially if buttons A-B and buttons 1-4 are far apart and the hand span is not long enough and the walkaround loco controller or tea mug is in the other hand... With Siemens mosaic panels I've seen the mosaic cover removal magnet being parked over a turnout group button to allow turnouts be thrown with one hand. I had a dream of adding flank protection to the plan (i.e. tying coils V2+ and V3a somehow together), but run into difficulties. I trust it could be done with point motors having no common lead, like Peco, but i just cannot get it right. One should always have equal amount of diodes for each simultaneously turning coils, else the one with less diodes will get most of the juice from the CDU. Again — thanks for the correction pekka [PS: is it customary here at RMweb to a) replace (or try to replace) incorrect schematic on previous message with a corrected one, or b) add a new schematic to later message, or c) leave it as it is?] / PSi

Would pressing two buttons -- like in NX system simultaneously be an acceptable solution? Double slip may mentally be "broken up" into two ordinary switch, like below: I'm using nomenclature used in Finland (and probably in Germany) to denote different ends of a double slip. The letters within coils of twin-coil motors will cause route to enter or exit at the track end with the same letter. As one splits the double slip into to two ordinary switches, the coils "mentally" look like shown above. Should you know this beforehand, then I apologise. As you mentioned that you already used a three way centre-off switch for the spur you would have connected the switch to the point motor denoted with letters a and b. The other motor you would connect to your diode matrix as an ordinary turnout. Now, if the pressing of two buttons atthe time is ok with you, then you could do something like what is shown below. It has in a way two diode matrixes, one at the "plus" side of the turnout motors and another at the "minus" side of the point motors: Note that the point motor V3 a/b is "upside down". By pressing button A or B at the same time as pressing button 1...4 will set the route between those buttons. Turnout V2 is thrown to direct route when the turnout V1 is set to diverging route. This is only to consume some energy from the capacitor discharge unit to prevent point blades of turnout V1 becoming loose from the throw bars, as suggested by DavidCBroad (I too have done that mistake myself at Tapiola club, see photos at https://taprk.org/eng/show/prp_2002/ ) Now there will be at minimum 2 and at maximum 4 motors operating at one time. Due to having diodes at the "plus" and "minus" side they will tax more compared to single sided diode matrix. If you can invest to another capacitor discharge unit, you could then feed button A with one CDU and the button B with another and have the minus sides tied together (make sure this is ok from the manual of the CDU of your choosing). This way the CDU for button A will fire 2 or 3 motors at one time and the CDU for button B will always fire two motors at one the time. I have not double checked the diagram, so beware of typos... Ah, and always use protection diodes or snubber diodes across the motor coils -- and beware of the polarity of point motor V3 a/b. pekka

One resistor case: what if the connection to frog is interrupted (wire loose, or point motor's internal switch develops a fault or the switch is just too slow): then the LEDs will be in series across the supply with no resistors! I too would put two wire bi-colour LEDs (those, that have two leads and which will have red or green LED inside the LED case on. depending on polarity, and yellow if fed with AC, like DCC), and two resistors into the schematic. It appears that many consider reverse voltages in excess of LED manufacturers datasheet's advice safe enough, as LED will operate like a Zener, and -- provided the reverse current is low enough when the reverse break down voltage is passed there is no eminent damage. If all LED manufacturers warn aginst reverse voltages, I belive one should not encourage or advice dismissing the warnings given by manufacturers, especially when the advice is given to a person apparently not yet quite familiar with the LEDs. I feel one should suggest to follow rules, and only cut corners when, due to experience, one is confident that one is knowing what one is doing, and one can estimate the risks. A document evaluating the suitability of common automobile usage of LEDs in aircrafts is rather interesting (the PDF will automatically load) from: https://docs.broadcom.com/docs/5980-1504E After reading this I went and crossed over my suggestion of using slow 1N4001 diode as forward protecting diode at at another thread here due to slow speed. Just recalling: I have made a DIY DCC decoder (based on Probst decoder https://taprk.org/eng/project/dcc/diary.html ) once that had the rectifier built from 1N400X type diodes that I happened to have laying around the desk. The diodes got quite warm with no load, as they were so slow to switch off at polarity change, and the bridge rectifier was shorting the track power for a short moment at each DCC polarity change. I should have learned from my mistakes... pekka