Gordon H

No, they're not. They only appear to be so because DCC has been seen as an easy route for achieving it.

Suggest you check your official drawings against pictures of the real thing before getting anything manufactured. A picture of the correct AMBR type - though not on an 86 - can be seen here: http://www.traintesting.com/images/mentor-roof.jpg Here is one on an 86: https://en.wikipedia.org/wiki/Stone_Faiveley_AMBR_Pantograph#/media/File:E3146_(8420382865).jpg

The one shown is not a UK style Stone-Faiveley. Its lower linkage is behind the main arm, indicating it is more like a Siemens type. Faiveley's have their lower linkage this side of the main arm (as viewed in the picture).

I hope they rethink using the pantograph shown in the picture and change it to the correct type.

Suggest you go with whatever sound you can get - then when someone else comes along and says 'that doesn't sound right for an '82', you can ask them what it should sound like. Until that happens, no-one will be any the wiser. :-)

They are not the same as Tortoises which are continuously powered 'stall motor' types. Kato points are solenoid based, and therefore must be pulsed to operate, not left powered. The only similarity is that they both use just two wires, where the polarity of the applied supply must be reversed when operated. A DPDT centre off switch could be used for control, but it must be a 'biased to centre off' type.

There is also the Elgin County Railroad Museum in St Thomas. http://ecrm5700.org/ Moving down in scale a bit from the real thing, there is the St Jacobs & Aberfoyle O Gauge display. Mostly open at weekends. http://stjacobsmodelrailway.com/

Count me in...

Rather depends on your personal definition of 'suitable'.

So long as the newly chosen name is equal to or longer than the printed one...

Your thinking is based solely on the notion that the only reason for having the overhead wire is to allow for a second loco. It is perhaps unfortunate that this was used as a selling point by manufacturers at the time, much like the 'only two wires are needed' notion for DCC. It is not a question of perceived obsolescence or expense - its a matter of getting as close as reasonably possible to how the real thing operates - far closer than steam (other than the discontinued Hornby items) or diesel outline could expect to achieve in the smaller scales. Overhead wires are part of the infrastructure of the railway, so in principle should have as much attention paid to them as the track itself.

Same here, but it would be nice not to have to go through that process for a change.

Sensible to you, as it happens to agree with your thoughts on the matter, which are clearly not those of a committed OHL modeller. Your approach appears to be based purely on the economics of the situation rather than achieving a properly engineered end result. I would rather pay a bit more and have it properly functional than suffer another example of the typical low-end compromise we are being palmed off with yet again. If you don't want to have wires why bother modelling a genre which by its very nature requires them? It appears the only way to foster greater interest in this field is to encourage modellers to try doing it for themselves. It would therefore be useful if the nay-sayers with their lack of vision would encourage people to do so rather than trying to persuade them it's all too difficult.

Some of the 86's had cross-arm pans (which Judith Edge produces), so you could choose one of those and renumber the loco as necessary.

Noting your location, perhaps you will be able to visit the MERG stand at the Peterborough show later in the year? https://www.world-of-railways.co.uk/shows/show/the-national-festival-of-railway-modelling/

An alternative to the resistor idea is to use a string of series connected diodes which will give a better defined voltage drop (~0.8V each) which won't vary so much with load. Use two such strings connected back-to-back to allow both polarities to work. A similar effect could be gained by using two reverse biased zener diodes in the same fashion, but strings of multiple conventional diodes would distribute the power dissipation better.

The main hall was like a sauna during Friday set-up, all day Saturday and all day Sunday.

The 'post reversal' picture immediately above should have the longer legs on the left hand side, not the right hand side as shown. According to this post http://www.rmweb.co.uk/community/index.php?/topic/110547-drawings-and-parts-for-classes-81-to-84-and-86-to-89/page-2&do=findComment&comment=2286563 the insulator spacings are 69 1/2" by 57" (Approx 1765 mm x 1448 mm, or 23.17 mm x 19 mm in 4mm scale) However, there is no definitive information given as to what the division is either side of the head position. In the past when modifying Sommerfeldt 968's with brass side frames, I have always assumed the shorter legs to be at a 45 deg angle, with the longer ones angled a bit less to suit the overall dimensions.

Can't help noticing that the base appears to be in a square formation, rather like the Sommerfeldt 968 uses. The 'forward' base legs should be longer than the 'rear' ones, as per the Hornby 86. Bachmann 85 etc. This was one of the most annoying features of the original Lima 87 when it came out - they had compromised the roof detail where the pan mounts to make it fit the square based diamond frame they adopted for it at the time.

I use a Proxxon KS230 table saw with a diamond coated disc cutter for working on fibreglass PCB material (FR4).

It often happens on models due to a combination of reasons. Firstly, the use of sectional overhead wires is prone to cause mechanical discontinuities in the flat surface the pan head should encounter. A continuous contact wire is much better in this regard, with the minimum number of joints used, typically only across baseboard joints. On the 85, its problems are due to the pan head linkage being incorrectly implemented, meaning that although it has a means of maintaining the head position, it does not have the true pantograph action required, i.e. the head should always be parallel to the base throughout its movement. On the 87 model, the cross-arm probably has no means of maintaining head position, other than upward pressure, where a kind of triangle is formed between the front and rear pan head cross members and the pivot point below, i.e. the slightest drag on the leading edge is likely to tip the head backwards. This is where a continuous smooth contact wire wins every time. The same can happen with scratchbuilt pantographs - which is how I know - and any tendency for the head to tip backwards is a sure sign of a mechanical problem with the catenary which therefore needs fixing.

You don't really want 'D' Type flip-flops for this. A Set/Reset latch type such as the CD4043BE would probably be better as you can then control when the previous number is cleared by commoning the Reset pins together. The 4043 has four such latches per package. You could instead form the latches from standard gates, of course, but that would entail considerably more wiring up. Do you actually need a BCD output? Wouldn't the resulting BCD value tell you which switch was pressed anyway? An alternative to the diode matrix would be to use a set of cascaded priority encoders such as the 74LS348. These would give a binary output rather than BCD. See http://www.ti.com/lit/ds/symlink/sn74ls348.pdf for an application diagram showing how to accommodate up to 64 inputs.

Just had a look at this, means very little to me. Doesn't seem to answer my questions at all. 'pulse_length' seems to be redefined several times, probably helps if you know what language it is written in. Personally I don't like using high level languages for this kind of direct hardware control.

So now we just need a European model manufacturer to decide these locos are worth modelling in this guise, preferably in 4mm scale as tooling will already exist. :-)

So does a laptop, but that doesn't make it a sensible choice either. Horses for courses applies. 375 ? What units are these? When you increase the number to move the servo, how many degrees per increment does this give? This is all rather meaningless in proper terms. A servo centre position is conventionally defined for a pulse width of 1.5ms. How do you relate the pulse width (hence angle) to the number you apply? I would suggest you adopt a scale/multiplier that results in conventional time units being used, so making 375 become 1500 (as in microseconds) would be much more understandable. Also, how do you set up the pulse repetition rate?