unravelled

Flying Scotsman Anniversary special 16/4/1966. Taking water at Hawick. Dave

LED lighting These are a few thoughts on LEDs from my readings, researches and experiences. Corrections or additions are welcome, I can edit as better info comes up. I hope it’s the best Lunester thread for this. It’s a bit general for the main thread so I edited out any mention of the unmentionable before posting it here. First, a useful faq page from Philips on led myths http://www.ledlightingexplained.com/led-lighting-myths/ Nowadays I think LED home lighting should be a no brainer, especially for heavily used areas. But perhaps for occasionally used lighting in a shed, the waste heat from incandescent lighting might be an advantage Watts and lumens One of the first things needed to compare LED offerings is the light output. The differing efficiencies of light sources makes wattage too confusing as a meaningful measure so lumens are the way to go If you’re used to thinking in wattages, as very rough rule of thumb, you need a LED wattage about one sixth the incandescent wattage for equal light output The output in lumens is very roughly 11 times the incandescent wattage, or 70 times the led wattage A useful page of conversions is at http://www.thelightbulb.co.uk/resources/lumens_watts For the maths and raw data see http://www.thelightbulb.co.uk/resources/lumens_watts Colour temperature Another variable which crops up more with LEDs is colour temperature http://www.lightbulbs-direct.com/article/colour-temperature/ The traditional incandescent bulb practically defines warm white, but LEDs bring the easy option of cool white and even daylight alternatives, helpful in getting a more outdoor effect for indoor constructions… A further issue arises because individual LEDs are small and have to be assembled in numbers to achieve the same effect as a more conventional light source. LEDs are also more directional than other light sources. This has a couple of consequences, the first is that LED arrays can be more directional than traditional sources, and the second is that LEDs can be easily assembled into lighting strings or tapes. One result of the directional nature of the light means that a flat array of LEDs may not give as good a spread of lighting as a bulb or tube. While the downside of this is that more thought has to be given to orienting strips so that the light is directed where wanted, energy isn’t being wasted on lighting up areas where it isn’t needed. An advantage of this the elimination of the need for bulky and costly reflector mountings to redirect light which would otherwise be wasted. However shades might be needed to keep directly led light out of the eyes. Replacing existing bulbs or tubes with an LED equivalent can be a bit underwhelming. I found the fluorescent tube replacements I bought were not as bright as the tubes they replaced. In addition I made the mistake of going for a warm white. There will be energy savings of course, but it’s possible that the positions of the fittings might not be ideal for the different properties of LEDs. Probably the most interesting LED products are the linear arrays often sold on the roll or in cut lengths, to run of a 12 v supply. But as always, this brings another set of decisions. Which chip Not all led tapes are equal. As well as the warm/cool/daylight possibilities, multicolour ones are available, with push button remote control. (No DCC option mentioned yet). Some are dimmable. some waterproof. Bought by the length from a local outlet they will be expensive, bought by the 5 metre roll from China they will be a lot cheaper. The other main variable in the white led option is the led chip used, this site describes them well https://www.instyleled.co.uk/support/what-are-the-differences-between-types-of-led-chip/ Which power supply This is an area I’m unsure about. A lot of the LED tape vendors make much of the need to use their special transformers to avoid poor performance and shortened life which other power sources might cause. Can anyone say if there is anything special about LED transformers, or will any well regulated supply of the correct voltage do. I can see that poorly regulated supply which peaks at well above the rated voltage might damage the LEDs and other electronics, but how fragile are these devices in reality? I would be tempted to use a good quality psu, run well within its capabilities, to avoid things getting too hot, never a good thing. Thanks Dave

I looked at a couple of the plans to see if there was any clue about the proposed trackplan. Both proposals I saw showed 5 through platform faces, with no bays. Other than the current stalled plans to reinstate one of the old bay platforms, I've only seen a couple of proposals. One to convert the current down platform into an island, (which matches these plans in part), and another to build additional bay platforms south of Botley road. I assume the entrants to this process were given an official trackplan to design around, so any ideas as to where it can be found? If this is going to go ahead, it makes me wonder if it's worth temporarily rebuilding the bays for the Chilterm services, if it is to be torn up again. It would be nice to think that the bays could be designed for conversion to throughs in the future It does however make sense of the decision to delay electrification through Oxford. There's no point in electrifying everything if its all going to change. Dave

The crews on the Chalford service also said that the driver wasn't always controlling the regulator.Is it omething which became more common as maintenance shortcomings made it more likey that linkages weren't free moving, or was it always the case? Davd

Looking good. Regarding the top, my preference would be to have the top rolling over and down, so that there is no chance of seeing the bottom of the backscene from normal viewing positions. I was half expecting you to do the fell by the old model boat hull method. Effectively draw all the contours on a couple of sheets, then on one sheet cut along all the odd contours, and on the other the even ones. The result should be a set of strips you can stack (and glue), with some additional support, to form the (stepped) fell, which can be carved to a finished shape. A risk is that it would be a bit more fragile than solid insulation, but once plasteredprobably strong enough. Dave

I'm looking forward to the next construction phase. There was some thought earlier about using a thinner trackbed across the bridge, to increase headroom. It might be interesting to choose some material or structure which emphasised the rumble as a train passed over it. Dave

The plan is looking better all the time, but is there still a a need for the reverse curve/wiggle at what is now the bottom of the plan? I don't remember reading an explanation for it, but could well have missed one. If the orange tracks were straight, or on a long (non reverse) curve. through the double junction, could the approach to the diveunder/flyover be smoother or more widely separated to allow more embankment/less retaining wall? Thanks Dave

I was too late to make this suggestion for your last bridge, and I hope I'm not too late this time if you are going for a multispan one. Often the central piers for such bridges are a pair of simple cylindrical tubes, sometimes wider apart than the bridge deck width, connected by a bearer for the bridge bearings. I guess that the real world advantage is speed of construction compared with solid piers, and plenty of worker refuge space compared with a continuous wall. The other common bridge design used for very skew crossings is the series of portal supportss at right angles to the lower line(s), or even a continuous tube, with a relatively light bridge structure for the upper. Few layouts have the space to model such arrangements, and I wonder whether one would suit here. It's good to see progress being made Thanks Dave

Just a quick question aboiy autotrailer formations. I believe that the limit was two trailers in front of the loco, which is why a four trailer train has the loco in the middle, but was it common to operate a two trailer train with a loco in the middle? I can see how it would be necessary in some circumstances, but what would the preferred arrangemant (if any) be for a 2 trailer formation. Thanks Dave

In my post 206 above, one picture shows a train leaving Brimscome with the driver apparently seated. Can anyone say whether the regulator position is consistent with its brisk departure (as I remember it), or is the fireman driving? In the picture approaching St Marys Crossing halt, it looks to me as if the driver is at the handbrake. Dave

I spent many hours at college reading old copies of the Engineer, when I should have been doing other things. Many thanks for the link. Dave

Crossrail MPG Plunstead by David Harvey, on Flickr Crossrail MPG at Plumstead

You can also get led "tubes" which replace fluorescent ones. They are more expensive than fluorescents, but a bit more efficient, and should save money in the long run. With the fittings I have all I had to do was unplug the starter, so the conversion is easily reversible. I have tried the led tapes, but found them a little disappointing. Not regarding light output, which is excellent, perhaps even too bright, but they can be a problem to mount. Recently I bought some 1m modules where the tape is mounted in an aluminium extrusion. These are much easier to put up. 12v plugtop supplies for them are easily sourced. I have found that some sort of fascia is needed with any variation of the led tape as the direct brightness is uncomfortable. Another point to notice is that there are several different sized led chips used, which may make a difference in brighness per metre. I can give details of what I've used if that's any help. Dave

A few pictures from 1964, of the Chalford services. I think they are the correct version. Some interesting weathering/distressing effects. At Chalford in the charge of 9711. Shows white line on cab droplight. Not much sign of cleaning above window level. There is paint loss on the cover strip between cab windows. Good job it's downhill judging by the empty bunker. Better view of white line on droplight. Any idea of the reason for this? Did someone suffer concussion trying to look in/out of a closed one? Looks like the same trailer approaching St Mary's Crossing Halt. Driver standing, possibly applying brake. Another trailer (W237W) leaving Brimscombe. Almost no paint on cover and corner strips. No cleaning above window line again. White line on droplight possibly narrower on this trailer. Driver seemes to be seated. Dave

Have you considered dismantling any of the old pointwork and reusing the parts, or are the components too specific to be adapted? Perhaps it's just me who finds dismantling things relaxing! I'm sure there are a lot of people, thinking about 00-sf, who would like a piece of pointwork to play with and test their stock on. Or even frame and put on the wall as inspiration. The problem I've found is that as long as storage appears to cost nothing, binning things isn't an option, but any other form of disposal costs time and money. My solution, when I can find a taker, has been to give stuff away, and ask the recipient to donate an agreed sum, or what they think it's worth, to a charity. My time/postage costs are then indirectly a contribution to charity, and I get some storage space back. Anyway, I'm glad to see the build restarting, and I hope you don't end up adding any more pointwork to the recycling box this time. thanks Dave

Definitely plan 3, the flexible running version, in my opinion. It was only the diamond, or rather the two consecutive points on the inner loop which I was trying to avoid in my earlier post. Dave

Looks good for play value, which is the plan. The simplification I'd make is to lose the diamond crossing and replace it with the upper left hand point it was connected to. You don't lose any operational possibilites, and trains can prototypically snake across the two crossovers instead. As for the gradients, I hope you are splitting them so that the front station area is at a mid height, then the blue curves can fall as the red ones rise. This will resut in more gradients, but shallower ones. As for the crash prevention, why not install a couple of kill switches which anyone can access, or do DCC systems have these as standard? Have fun Dave

I chose these as a cheaper and quicker alternative to building my own. I haven't needed to do any programming yet, as full servo travel was OK for my purposes. Dave

If I was going to build pointwork for my mainly rtr layout, 00-SF would be my choice. To me it's a no brainer, but I am over 65 and have an engineering background. My main reason for building track would be for bullhead rail and better sleeper spacing, not running or crossing appearance, but it would be silly not to take the opportunity to take the small extra step to 00-SF. As to whether I will get round to building my own track that's another matter. As I'd use it 00-SF would be a tweak to pointwork construction, rather than a standard adopted layout wide. To me it almost seems too simple to be a standard. Regarding gauges for back to back. How about a tapered plate between the rails, just roll stock down until it wedges. Add graduations for quick readout. I don't have the tools to make a very accurate one, but may try lasercutting something, to see whether 00-SF is appropriate for my stock. Thanks Dave

Would Bachmann Scenecraft 44-542 - Concrete Platform Lamps x 4 be any good as a starting point? The lamps are wrong, but the columns are octagonal, and not a bad match for the photo. Dave

Lots of things getting in the way of progress, but work is continuing. I've almost got the storage sidings finished, and writing that up is on my lengthening to do list. I'm glad to say that I haven't felt the neeed to change the theme or timeframe of the layout, and as a result I'm trying to dispose of some "wrong" stock. It's good to know someone else has chosen the same prototype. What was your reason for modelling Thame? I hope you make some good modelling progress this summer# Thanks Dave

The other issue which arises with G1 is that of power supply. You usually cannot run 2 rail electric and steam/older stock together because of lack of insulation on wheelsets. Of course radio control is very practical, and probably the best option these days. But budget for insulated wheelsets if you want to be able to run your stock on 2 rail layouts. I'm sticking with stud contact for legacy reasons, but new items will generally be battery R/C, (and 1:32). I hope we'll see some followup posts here Thanks Dave

Without being over precise, the difference is about 5%. Say about a couple of mm at buffer height, about 5mm at highest point. With the great variety in actual vehicle sizes, some mixed scale combinations may be hard to spot. Although the majority of my stock is older, so 10mm, I'm tempted to move to 1:32 for anything new, to match my Brassworks pannier. Unfortunately I'm also being tempted by the 10mm Woodbury Models planet, on the grounds that it's so small it won't look overscale. Thanks Dave