Please could anyone give me some general guidance about which sort of rolling stock used which sort of wheels (spoked, 3-hole disc and plain disk). I guess this might be a subject in itself so any rough guidance would be appreciated. Thanks Roger
A very quick response based on LSWR and SR practice:
Wagons - until circa 1930 the majority of wagons were built with open
8spoke wheels, thereafter the majority with 3 hole disc (so they could be spragged). Closed spokes also used say between 1920 to 1950. - need to check reference books for which companies.
Always some oddities - so the SER adopted Mansell wheels (see below) for wagons, I think one of the Cumbrian railways used 10 spoke wheels, certainly the LSWR used same for stone block traffic - loading to 15 tons.
Coaches - Mansell (an SER employee) patented his wheel about 1848 - this had wooden segments between boss and rim. Superseded by steel discs early twentieth century - first LSWR use under Ironclads about 1920.
It depends on what period you are modelling and as requested, I give 'general' guidelines. In more recent times (60's onwards), wagons generally used 3 foot diameter wheels (12mm diameter in 4mm scale) and coaches (MKI's and many pre-nationalisation coaches) used 3 foot 6 inch wheels (14mm diameter in 12mm scale). MKII's and MKII's use smaller wheels. Wagon wheels were generally 3 hole disc whereas coach wheels were solid (well, they actually had very small holes, but these are rarely modelled). Spoked wheels were generally not used on wagons with vacuum braking as solid wheels were stronger.
These are general guidelines. There are exceptions to these 'rules' and in very recent times with the advent of the latest rolling stock, wheel sizes come in all shapes and sizes!
As others have suggested, Paul Bartlett's fotopic site is an extemely good reference.
Surely it's the wheels that are spoked and three-holed, not the axles? :-) Although I guess you mean one axle of spoked wheels and one of three-holed on the same wagon. Don't forget, there are also some pictures around of axles with different wheels on them.
I can see I shall have to watch myself :) But different wheel types on the same axle is a new one for me. I assumed they would be mounted and turned complete, mixing them ought to offend the sensibilities of any half-decent machinist.
The GWR also adopted - or rather reused - Mansell wheels under some of its post-1930 freight stock. The Diag N16 horse boxes used them, as did the open carriage truck (whose code escapes me at the moment - Scorpion?). These were counted as "brown vehicles" (freight fit for attaching to passenger trains) and Mansells were used probably for the smoother ride required. Worth looking at the pics in Jim Russell's book - 1930 vehicles but the underside was pure 1910, complete with the elegant springs and hangers, and longitudinal tubular gas tank. At a guess Swindon was reusing scrapped four-wheeler coach components.
I mention this in the modelling context as one of the items still going the rounds is the old Triang N16 horse box. The body moulding is OK, the roof features are dubious but upgradeable, but the solebar, irons and wheels are utterly wrong, using the blodgy generic Triang LWB wagon chassis moulding. To get a decent model will require a set of Mansells and associated bits - Ratio components might be ideal. Guess who's got a boxful?
Now if someone can tell me what freight and carriage wheels pre-1850 were like...
I've not seen spoked and disc wheels on the same axle, but sets with one side having tread brakes and the other disc brakes are common, being a feature of the HAA hopper family. Not sure how wheels/axles are assembled in the UK,but in France wagons carrying various sizes of wheels (without axles) are common at Grande-Synthe yard, Dunkerque, there being a steelworks nearby which manufactures them. Brian
That surprises me - I would have expected heavy braking to throw the wagon over to one side - assuming the wheels are coned.***
Can't believe that the pairs aren't turned after fitting to the axles, a tiny discrepancy at the axle stub results in a large eccentricity at the wheel flange. Any fitters out there who can help us?
***In fact the difference in braking efficiency is such that I would expect the wagon to leave the track. Do you really mean different braking on each side, as opposed to each end of the wagon? Imagine having calipers on the right side wheels of your car and drums on the left.
Bomardier bi-level coaches, as used by GO Transit in Ontario, have one external disc brake on each axle, on alternate sides (modelled in HO and N by Athearn). Can't find a detailed pic, but here's a description:
Train axles don't work like your car, there is no differential, so it doesn't matter where on the axle you put the brakes the braking effort is transmitted to the rails equally through both wheels hence no leaving the track or throwing to one side. Applying the brakes to only one wheel of the pair is a common arrangement, mixing disc and tread brakes less so. Keith
Not that uncommon, though, as over 11000 HAA and derivatives were built. Another variation is that used on some SNCF container wagons passed for 160 kph running- they have tread brakes on both wheels of both axles (used at low speeds and for parking) as well as axle-mounted disc brakes. I believe our (Eurotunnel) second-generation freight shuttle wagons use a similar system- I must have a look when I get a chance. Brian
Tread brakes are more efficient than disc brakes at *slower* speeds.
Slightly OT, but 156 DMU's have tread brakes and 158's have disc brakes. Tread brakes are better in leaf-fall season because they clean the leaf mulch off the wheel treads. A temporary fix a few years back was to create
156/158 hybrid pairs to try and minimise the problems with leaves on the line!
Cheers, Mick (Waiting for the DRS 37's to pass on the water cannon...............)