DCB

Last evening I fired up my (t)rusty lathe and made a track gauge. Triang Coaches with Hornby wheels have been derailing at a couple of points on the layout and I suspect the track is wide to gauge coming off the lift out section. I carefully marked up a bit of brass rod and cut a couple of grooves to match a bit of streamline track, double checked it with a 3ft radius point and also a but of awful "GT" track. and deepened the grooves to snugly fit over the rail heads. So far so good. I then reduced the diameter to leave effectively 4 collars around a slim shaft so I could check the gauge part way through points. Still so far so good. I then tried the gauge through some streamline points. They were tight to gauge. The frog end curve went from good to 1mm tight in the 15mm or so of the short rails which are straight whereas the long rail has an even curve. Worse still my set track, Triang Series 3. std grey, and Super 4 are all tight to gauge compared to streamline by quite a bit. Can anyone explain? Is Triang really 00 sf gauge?

The terminating passengers were Marlborough Branch workings mainly just running to Marlborough and back most of the photos I have seen show a 4575 on these duties. The District Controllers View MSWJR No11 (Express Publications) lists the Marlborough - Savernake west shuttle as a 45XX duty no SW 77 in 1955. I'm now wondering if there were there any pick up freights between Savernake West and Marlborough serving Marlborough, or did they all go via Savernake High Level working out of Swindon.

Sounds to me like pickups dragging on the wheel spokes. The click sounds too fast for anything dragging on the sleepers. In my parallel universe 92251 would be one of the Caprotti class 9Fs fitted with Giesel ejectors and mechanical stokers.

The zener was actually totally reliable, unlike every other system of voltage regulation I came across it did not have any moving parts and did not restrict the amount of current below its operating voltage. I converted a lot of 1960s British 6 volt motorbikes to zener diode and capacitor 12 volt systems with decent resin encapsulated rectifiers in the 70s and 80s with a big weight saving dumping the battery and alternator secondary output switching and no problems. The only real issues with a Lucas Zener in train controller voltage limiting situations are how you connect it, before the reversing switch or through a rectifier after the reversing switch, and the cost, new the damned things are now very expensive. It should not get too hot on a normal 2 amp controller even on full output off load as they shunt 80 watts continuously in motorcycle applications, Edit, The problems of excess voltage spikes damaging motorcycle electrics is mentioned in a motorcycle magazine this month, I think it is something about sports bikes with a Blue Kawasaki H2 two stroke triple on the cover. It mentions making a peak voltage tester using a rectifier (for AC) capacitor, resistor and DC scale on the Multimeter. The Lucas Zener system minimised these spikes.

Just been checking the cost of Lucas "12 volt" Zener diodes on ebay, anything from £3 to £1200! High power zeners seem to be old hat and low power zeners as part of an electronic regulator seem to be the modern way. No reason you couldn't use such a regulator on the outputs provided you had a bridge rectifier in circuit to protect it from reverse current. You could use a string of diodes to drop the voltage as I do with a 12 position rotary switch and diodes connected between the contacts so as to give full voltage, 10 progressively reducing voltage steps and an of position. However these drop the incoming voltage, they don't limit the track voltage. Using this switch in series with a resistance controller gives some very weird characteristics so wouldn't recommend it The usual place you find this set up is old Analogue Scalextric sets and the two controllers off one power unit affect each other so much that backing off your cars power abruptly when your competitor is part way round a band will send them spinning off. I use separate transformers for each controllers to avoid this. This can also happen when some circuit controllers are piggy backed off transformer controllers as you speed one train up and the other slows. Can also cause some same side dead shorts and I think if used on common return the wiring would simply short it out unless both trains were moving in the same direction.

If you are desperate to keep off load voltage down you could use an off the shelf Lucas Motorcycle Zener Diode and heat sink, as used on 1971 to 1976 BSA and Triumph Motorcycles with the unregulated permanent magnet alternators. These used 10 amp/hr batteries or for off road a capacitor in place of the battery, a capacitor about the size of those used on a typical CDU. These Zeners are capable of keeping voltage down to around 14.5 volts from 2000 to 7000rpm whether the lights are on (80 watts) or off. The Zeners come in - ve earth and + ve earth versions and the heat sinks get hot! On the other hand a decent Morley Vector or similar will keep the off load voltage down if that is an issue but to be honest I can't see 24 volts DC making any difference to a DCC decoder. [Edit,] as NMRA standards require decoders to be OK on27 volt DC

Sounds like a reasonable assertion to me, all the videos I have seen of Heljan models have the return crank outside the con rod fitted so as to give an eccentric motion whereas in the prototype it would have been concentric to provide an anchor. I suspect Heljan originally assumed it had Walschearts gear as per the GWR Vale of Rheidol 7 and 8 (as do most modelers) and that the outside rod has to waggle about (as do most modelers). Might be an idea to simply fit Walschaerts gear and 99% of buyers would think it was great.

Savernake (East) was a unique place where you would find a Manor or 43xx or Southern U class mogul stopping at the platform on a three train coach train and then a couple of hours later a Kings hauled 13 coach Cornish Riviera Express would rush through non stop as some of the MSWJR Cheltenham - Southampton passenger service and the GWR crack Paddington - Devon and Cornwall express services all used the station. In fact the ratio of non stop Express Passenger trains to Pick Up Goods would be about 6 expresses to one pick up and probably a dozen through freights to one pick up, however then as now many through freights ran at night. (Which is why I for one don't model many of them.) There was not much mineral or through coal traffic on the Berks and Hants, it went Swindon -Reading on the original GW main line. Equally Tank engines would probably have been quite rare at Savernake East though Swindon based 45XX operated from Savernake West to Marlborough. A Ratio of 10 Kings or 20 Castles or Halls to 1 tank engine, is probably about right. ( Incidentally all the 20 or so Plymouth and Old Oak based Kings passed through while only the 2 Gloucester based Manors were normally seen there.) Getting even further off topic, Swindon, Gloucester, Eastleigh, Old Oak, (Southall?) and Plymouth sheds definitely had duties through Marlborough, Probably Newton Abbott, Reading and Westbury maybe Taunton and Exeter as well so the variety of locos was pretty extensive even though the number of trains was comparitively small compared to the Reading - Didcot main line.

Sidings sloping down towards the exit points and running lines being on a downward gradient both caused challenges. I think Mottram yard near Manchester on the GC line used gravity for all its shunting instead of using shunting engines. Full size railways don't use baseboards so getting sidings level is not usually too onerous. However apart from wagons escaping backing steam locos uphill for shunting was not good, a rapid start or stop could lead to water uncovering the firebox crown causing the fusible plug to melt and allowing steam to escape into the firebox so stopping the loco. So when there was any appreciable gradient the sidings tended to slope downhill from a rising gradient. The siding at my own local station, Chedworth MSWJR was accessed of the downhill gradient and were never opened to the public. Probably because of this very issue. Subsequently Chedworth Woods siding, also accessed from a downhill slope, probably 1 in 75 were shunted by a loco running tender first to avoid problems with water surging.

A bit like asking "How long is a piece of string." If you can find any old railwaymen ask them how they shunted but they are getting old and many of them simply didn't take much notice of the detail, the youngest WR steam firemen are now 74 remember, 18 in 1965, and many small stations and yards had closed by then anyway. Adrian Vaughn's books give some insight into workings.

Hornby Dublo wagons struggle to run on a 1 in 50. I actually used to use an old mainline coach as a spirit level as it would run on less than 1 % grade. I suspect placing a small super neo magnet or 50 in strategic places to attract metal wheelsets may work, we hear of Kadee uncoupling magnets attracting steel wheels being a problem. Otherwise a brake operating on one or both axles on a brake van could be good. I have one planned but making it work is not easy, split chassis pick up operating a solenoid is do able but the actual mechanism is a nightmare for DC. DCC should be easier but Putting a power bogie under a van sounds a bit OTT unless you want a cut price Toby to keep Thomas the Tank company.

Can I make a rather blunt assertion that this is the opposite of what you want for testing. It will deliver a set VOLTAGE and vary the current according to the demands of the motor, disguising any tight spots and potentially damaging the gear train. However add a centre off DPDT reversing switch and these will potentially make brilliant controllers for the layout or for running in, very smooth quiet speed stable operation, no angry Bee PWM buzz...

"The West Highland" do you mean the Glasgow to Ft William or the Mallaig extension as the extension was more likely to see 2-6-0s and the Glasgow line 4-6-0s by the 1960s. The 4-6-0s were a bit too "Big in the wheel" for the Mallaig line (still are comparing the way a Black 5 struggles out of Glenfinnan where the K1 eases away effortlessly...) but their speed came into its own along the Clyde coast when they had to keep out of the way of the Suburban trains. J36s were used as Ft William Pilots and I think they dumped the 4F there to get it as far from Eastfield as they could, did it have a snow plough? I think steam ended in Ft William in 1962. Ft William is a great subject for a model whether old or new stations

Good advice, if it will run smoothly on one of those it will run smoothly on anything.

I have done the Romford conversion in the past, however the crank throw on the standard Romford wheels is very short and they change the appearance of the locos quite considerably which is why I am turning down Triang flanges. The Markits "Triang" axles which fit directly into the chassis and the knurled ones take the gear wheels directly make re wheeling these models a lot easier than the old Romford 1/8th axles which needed bushing. Power bogies are a bit difficult as ideally you need to fill in the spokes in the standard Romford 14mm etc wheels with Araldite or similar to represent disc wheels and they benefit from shimming the gear wheels to take the side play against the chassis instead of against the backs of the wheels which seems to make the wheels come loose. Without shims the wheels have excess sideplay which plays havoc with the pick ups and can lead to large steam locos being out gauge as they crab down the track.

The last GWR stations were built as light railways, the Wrington Vale being one and the stations had 4 points, one each end of a long loop and two sidings, both through and terminus stations used the same track plan. Many had a goods shed on one siding. Loco sheds were only provided at terminus' in earlier years, later practice kept locos at larger sheds almost always on "kick back" stubs so a runaway loco could not escape to the main line if left in gear while raising steam.

There are plenty of X04s and the like available on Ebay and elsewhere and super Neo magnets which improve their efficiency. Carving a milled brass chassis to take a motor gearbox is probably more hassle than simply finding a brass strip, or etched chassis if you really need a motor / geabox. My K's cast 42XX snapped a few coupling rods and crank pins in its brief career with very low gearing and an X04 and currently resides in my scrap box. I find the 5 pole Airfix motors are comparatively gutless compared to the X04 and need lower gearing for main line work. If the 42XX chassis is intended for Romford gears there should be no problem using a 50:1 or 60:1 gearset. The problems come when the Airfix motors are used with a standard X04 gearset. The Airfix have better brushgear as the brushes are shorter and the diaphragm below the top pole piece which can ease the problems with taper boiler to live brush clearance. In many ways a 3 pole X04 armature in an Airfix frame is the optimum.

I have read that GW 48XX (14XX) had a cord connecting the Auto trailer controls to the Loco whistle chain when attached bunker to trailer, I read it in a fireman's reminiscences about the Faringdon branch where the loco left the trailer to do some shunting and the fireman forgot to disconnect the cord resulting in the whistle going "peep"... I will try to find which book. Didn't see anything about smokebox end.

I think the prototype had smaller unpowered wheels. Are the traction tyres snug in their grooves. Are the points flat. They do tend to go hump backed if not pinned down firmly and the 31 has quite a long wheelbase. Do the idler wheels move freely? My battery powered Lima 37's floating unpowered centre wheels foul on the replacement CD motor and the motors have to have the lower edge ground away. B to B sounds suspcious, Both too wide so the check rail does not do anything, and too tight so the wheel rides up the check rail are equally bad. I use 14.2 sliding fit which is about 14.5 actual.

The Lima 4 wheel chassis just needs a CD motor, a bit of plasticard with 3 holes, 2 screw holes and a big one for the rear bearing bulge on the motor and a scalexric drive pinion. 6 wheel need a slim motor or the centre wheels foul. I might have another go at a Hornby chassis using Mersey507003's methods later, instead of trying to fit a Triang Dock shunter chassis to a Airfix / Kitmaster City of Truro (yes seriously)

The CD drive motor fits the Lima derived chassis with a ring magnet while the one in the photo is the old 1980s Hornby variety. I have several Lima chassis with CD motors but I have not managed to fit a CD motor to a Hornby chassis, sleeving the drive gear to suit would be a challenge as would grinding enough off the motor housing to fit the CD motor. My son's Hornby HST goes like a rocket so maybe it just needs a service

Which leads nicely on to whether bankers should be coupled to the train, I understand that the Midland didn't and the GW did couple bankers. The Lickey bankers dropped off at speed at Blackwell (?) summit and there are tales in "Firing Days at Saltney," of 3F 0-6-0 Tender engines used as bankers on Camp Hill bank chasing after the train they were to bank (on goods lines) and dropping off at the summit, or where the bank eased. I understand the GC didn't couple the bankers on the Worsboro' incline either but that was a goods only line, and that the SDJR used a special slip coupling operated by a rope from the loco cab. Now that would be a challenge, DCC 3 link couplings etc...

The Midland main line expresses out of St Pancras were accelerated in the mid 50s and many were too heavy for 6P (Jubilee) locos and Black 5s and really required a 7P, Scot, rebuilt Patriot or Britannia so the Jubilees and Black 5s were piloted, and rather than waste a useful locomotive they dragged some 2Ps off branch line duties and probably the scrap line and stuck them on the front of expresses on the basis that they could probably just about manage to pull the 30 ton or so overload... I don't know much about Cumbria, always sounds like Black 5 territory to me, with the occasional Mickey Mouse after the last LNWR Cauliflowers finally fell apart. I guess the coast line is fairly level buy the line across to Penrith was anything but with lots of pics of Mickey Mouses (Ivatt 2mt's) double heading on as few as 5 coaches. I guess f they sent the Mid Day Scot round the coast it would only have had a pair of Black 5s, I don't think Stanier Pacifics were allowed in BR Steam days. As Timbowilts says Pilotmen rather than Pilot Locos were provided for diversions where the Driver, and sometimes the guard, did not know, or did not sign for the road, lots of anecdotes in various enginemen's reminiscences, Drivers getting upset with Pilotman's handling of "His" loco etc.

There were hardly any two alike by the end and different cab styles at different ends were common. Get some photos of 47524 and compare them to your models.

I have a one yard long isolated section in the platform just over 1 loco length from the platform end so train loco can be isolated and the pilot can back down and couple up, the up end of the platform is one section and the down end a different one so a banker can come up behind. For trains taking a pilot from the hidden sidings or terminus the Pilot and Train engine couple up in the loco sidings where there are lots of isolated sections before backing on to their train. This needs designing in to a layout from the outset, but with 1 in 30 gradients and 7 coach trains pilots and bankers are a necessity. Uncoupling is usually in the loco depots after the stock has been pulled off. Most railways put the Train engine on the front including the GWR. But between Newton Abbott and Plymouth different rules applied and effectively any loco with a bogie could act as pilot despite the fact that Bulldogs, Dukedogs and Manors could not release the brakes effectively on trains of more than 10 coaches. Normally 5'8" wheel locos were used as pilots here but from Stratford on Avon 2251s were often coupled inside Counties etc for the leg to Birmingham. The SDJR often double headed 7ft wheel 2Ps with 4'7" 2-8-0s and 5'2" 4Fs, the Midland put 2Ps in front of Jubilees following accelerations on the line out of St Pancras, don't know why, it would probably have beet better to leave the 2P in the shed. Banking needs more thought, Tension lock couplings tend to ride over each other when pushing, so I use Peco type (Kadees would be better) and I make a coupling mounting bar which is guided by a pin engaging in the bogie or pony truck but free to float up and down between so the coupling does not lift and derail the leading wheels. I regularly push 20 wagons over a code 100 long diamond and up a 1 in 30 and around a short 3rd radius curve.