Guy Rixon

I understood that non-pooled wagons had to be returned empty, not with a back load. Back-loading was only possible with a special agreement between the companies. It was the amount of empty running that lead to the pooling arrangements of 1916 and later.

The finesse of 3D printing leads me to put in a lot of detail that will not really be seen. Earlier today, I was correcting square nuts to hex on one design because accuracy. And I have some axleboxes where I did two prints of the same basic design because the lettering on the front was different. I can just read the writing on the print with a 10x magnifier. My excuse is that eventually I get asked to scale these designs up and then the detail become necessary. Easier to put it in from the start.

The red in the first photo is a very thin coat: we can see the wood grain through it, whereas the grey hides most of the grain. I would expect a old-school red-lead undercoat or top-coat to be thicker, ditto for a modern undercoat. I suspect that the red layer is not paint, but a wood-preserving stain. The red in the bottom photo looks like paint. If the wood is treated with preservative stain, then my hand-waving guess is that it's modern. I'm not sure that the preservative was around c.1903. I note that the grey coat was applied after the wagon fittings were put on, as witness the last photo.

Quite. Some engineers, notably Messrs Stirling, favoured domeless boilers because the dome complicated and weakened the pressure vessel. Domeless boilers were more prone to priming and tended to be replaced with the domed kind if the engines were rebuilt.

I suspect that there are two sets of safety valves, set to different pressures.

Yes, making a hemisphere is easy in most tools. If the dome is just a hemisphere sat on on a cylinder, then it would be trivial. In OpenScad, and possibly other tools, this is more easily done as a sphere embedded up to its equator in the end of the cylinder. If the dome has more subtle structure, then it gets harder. Making the dome cover flare out to meet a flat surface at its base is quite involved in OpenScad. I have a hack that can do it. It might be easier in other tools. Making that flare meet the curved surface of the boiler cladding is properly hard. Note that forming the flare with full, rotational symmetry and then carving a space for the boiler does not answer: the dome cover is typically flared to the boiler all the way round, meaning the flare happens at different heights for the various angles. It's almost as if a rotationally-symmetric flare has been stretched to form a saddle... ...which may be the way to make the model. OpenScad lets one apply arbitrary transformations if one knows the maths, and a saddle is just a space with sharp, negative curvature; which is a standard solution. I'll look into it, but it may take a while; I have a few other virtual models in the queue. BTW, given a CAD, it's possible to have a dome printed in brass and polished by Shapeways: they print waxes and then do lost-wax casting. Would this be of use? Also, the one one kind of dome that I could draw easily is that on some early engines. This had a cylindrical dome-cover with fluted sides, a top that was not a hemisphere and a box where the cover met the boiler cladding.

I use OpenScad for 3D modelling. It is not well suited to subtle curves, but it might manage a dome. I would need to derive a series of points that represent the dome profile in 2D and then the software can do the rotational extrusion. The finished surface would be facetted between each pair of points, so many such would be needed for a good finish. I can't see an easy way to model the saddle at the base of the dome in OpenScad.

I'm not claiming that the colours on the preserved stock are definitive. I think there is now no definitive reference for these colours. Therefore, it would be really hard to call Bachmann out on an error in shade when we don't really know what is right. Bachmann's colour, as I can judge it from the catalogue photos, look like the colour on the preserved, ex-LCDR coach, and I'm happy with that for the 1899-1911 period. However, if one is looking for actual errors, consider this: I think that the 60ft coaches were introduced in 1912 (I'm on holiday and don't have my copy of Gould with me to check). If this is correct, and if the livery change from purple lake to crimson (see my previous post) was also in 1912, then the 60ft coaches make no sense in purple lake. They would have been crimson when new and then brown from their first repaint; then presumably brown until the green, SR livery came in.

Worsley Works do etches for the shorter coaches of the birdcage sets. Concerning the lake colour, I like the colour used by the Bluebell Railway on their preserved, ex-LCDR stock: Note that is is definitely purple-brown; not a very blue purple, not a plain brown and certainly not red. The perceived colour changes with the illumination. Here's the same coach in brighter sun, looking less purple. Note also that c. 1912 the SECR seems to have given up the purple lake and changed to a brighter crimson, which the preservationists render like this: This crimson phase comes, IIUC, before the change to wellington brown. The lined crimson would be Mr. Wainwright's choice, shortly before he retired, and the brown (which may have been the lake base-coat without the fancy varnishing) started under Mr. Maunsell.

I found this picture of another kind of Huntley & Palmer's wagon. Dunno if it's any help.

Could they be hired wagons? I see no reason why they'd be in a separate number-sequence if the SECR owned them. EDIT: D'oh! Re-thinking my previous post, possibly C for Cory's, implying that they were owned by the SECR but on hire to Wm. Cory. But that is conjecture.

Birmingham New Street. Not because it is now a bad station, but because I know how much better it was before the barbarians buried it.

Railmatch varnish works well for me, on acrylic and enamel paint and on transfers.

At about this date, the SER, and then then SECR, seemed suddenly to need a lot of mineral wagons. I think it may represent the start of an arrangement with Cory's (one of the big, London coal-factors) to ship a lot of coal to wharves on the Thames and Medway provided that the railway provided the wagons for onward transport. Anyway, around this time the railway bought wagons from the trade, second hand from from merchants and factors, and from Ashford works. The ones from Ashford at this time were SER designs, and at least some of those built by the trade (e.g. by Hurst Nelson in 1902/1902) had SECR design-elements. I don't think that they would have used MR drawings for an obsolescent, 8-ton design in an order to the trade. Therefore, I suspect that the MR-type wagons bought in 1898 actually already in existence, presumably in MR stock, and were bought because they could be had quickly.

A clamp with a screw is more controllable than one with a spring. A bench vice might do the job well, if it has smooth jaws. Otherwise, a small tool-maker's clamp is very good. Even a large G-clamp could be pressed into service. Parenthetically, I've never understood why people model in balsa. If weight is not an acute problem, why use such a fragile material? There are many, stronger woods that can be got easily enough. I favour thin plywood and the sticks from Magnums. Also, medical tongue depressors - basically large lolly-sticks - can be bought on-line at a tiny cost for a small batch of a hundred or so.

If one zooms on the SER open next to the wood pile, it's somewhat interesting. Its springs are mounted in shackles, not shoes, and it has a lamp iron for a tail lamp: these are fittings the SER used for its faster goods services. From the 1880s, all the SER opens were equipped for fast/through working. However, this one is presumably an early wagon because it has the early kind of buffer guide and single-shoe brake. It's hard to imagine how a non-fitted goods could operate without a trailing brake-van, but it looks like the SER got away with it at some point.

Reducing the solebar height is not so hard. I do it by laying a large file flat on the bench and moving the solebar against it. I check frequently against the headstocks to avoid taking too much off at one end. Where the curb rail hides the floor-solebar joint, that joint doesn't need to be visually perfect all along the length. It would be OK to have a slight gap in the middle.

Umm - so when are you? Does it actually mean anything? Suppose you and I are sitting together drinking tea. You tell me the time on your watch (or on the posh caesium-fountain clock that you always carry with you, coz finescale time is important, right?). We drink another cup of tea. Your watch now shows a different time. We are right next to each other, not moving together or apart, so where we are, relatively, hasn't changed. But when we are has changed. Proper time passes whatever we do. A sage once said that we can never step into the same river twice. Empirically, however, we can throw the physicist into it as many times as we like if he keeps annoying us with details.

To tell time when travelling relativistically, just use a good, atomic clock. That gives the proper time where you are ("proper time" is a term of art in physics, but for once it have about the same meaning as the day-to-day usage.). If you want to know when someone else would observe events in your frame, you have to do the dance with the maths, allowing for relative speed and depth of gravity well. There is no physical clock that gets you round this. Current theory is that such a clock can't exist within the observable universe. If you don't have a clock you could try observing a pulsar but they're a bit pants as clocks. Most of them spin down over time - the time between pulses gets longer. A few might spin up - pulse interval shortening - if they're in a binary system and accreting angular momentum from a companion star. Most of them have internal stresses that get relieved occasionally by "starquakes"; this shifts the mass around internally and changes the spin rate.

If you fit axleguards with working springs from the Bill Bedford range, they're a bit wider than prototype. (This is for the ones sold separately, not the parts from Bill's kits.) The solebars need quite deep recesses to avoid their outer faces being too far apart. I suspect that there are a lot of model wagons where the visible faces of the solebars are too far apart. I know that a lot of mine are like that, although I'm trying to avoid it in new builds.

You might care to read about Barycentric Coordinate Time (TCB): https://en.wikipedia.org/wiki/Barycentric_Coordinate_Time. Note also the link in the first paragraph to the wikipedia page for gravitational time dilation. Working in space astronomy, I have to do conversions to and from TCB all the time. It's about as much fun as stabbing oneself in the face with a table knife. Essentially, the time of observation of a distant event depends on where the observer is (because of light-travel time; observers nearer to the site of the event see it sooner); how fast the observer is moving (from the time effects of special relativity); and how deep in a gravity well the observer is (because of the time effects of general relativity). TCB is a common reference-frame to eliminate these differences and to make event timings inter-comparable.

You mean the narrow-gauge railway in the Ramsgate tunnel after the SR closed Ramsgate Harbour station?

I got my 2.1mm drill-bits from UK Drills via eBay: http://www.ebay.co.uk/itm/10-x-2-1MM-HSS-DRILL-BITS-QUALITY-JOBBER-DRILLS-2-1-MM-/250851551455

Are Oxford's splashers the correct distance from the centreline? I would not be surprised if they have been moved in from the true spacing to match the 16.5mm gauge.

The Lanarkshire Models buffers I've tried have spigots wider than 2.0mm. One set were a push fit into a 2.1mm hole and another set needed their 2.1mm hole opened out with a rat-tail file. 2.1mm drill bits of adequate quality can be had cheaply on eBay. Fitting with the end flat on the bench but fixing at after body assembly is good. If you happen to be fitting the internally-sprung kind of buffer, it's pretty much essential. I always paint these off the wagon (remembering to spray them at the same time as the wagon where appropriate), then assemble them, then fit to the wagon after all the nastiness with transfers and spray varnish is done.