FarrMan

And quite a few others in the family were lighthouse designers as well - quite a family. Lloyd

I think that someone is mixing up the Lighthouse Stephensons and the Loco Stephensons. Robert Louis was of the lighthouse genre, and in fact constructed a breakwater at Wick Harbour, thou it was almost all washed away in a storm only a few years later. I think he may have written a book or two as well. Lloyd

Exactly my thoughts as well. Lloyd

Tony I think that it can be summed up as 'empty vessels make the most noise'. Now I had better shut up. Lloyd

Tony Is goof measure the ki8nd of measuring that I would do? Lloyd

Clive On that basis, an A1 would be better than an A3 or an A4. I think that your argument comes a bit unstuck there! If there had been an A0, that would have been even better. Lloyd

The better one is that when someone asks you if you have come from far, you just say yes. Anyway, exhausting day and DEFINITELY ready for bed. Lloyd

Keith You are, of course, correct. I hadn't read your response well enough. I had it right on the spreadsheet, but put it the wrong way round when explaining it. I go to the bottom of the class. I enjoyed both music and maths, though the maths got a bit boring doing so many examples when i had picked it up after the first few. Family house move not left Linlithgow yet. Apart from emptying lots of plastic boxes and generally getting things ready, my main part does not start until they reach Tomatin and my daughter in law comes here to Farr to pick me up to help unload. Then tomorrow morning moving the rest of our own stuff from where we lived until a couple of months ago (only a mile away from here) to their house in Tomatin. Then Friday night preparing a handle for his spiked roller (for a concrete floor screed), either using a broom handle or the arms of an old rotary clothes line! Should have peace again Saturday afternoon.

It is a while since I marked any Maths exams, and I was once told by an SQA external verifier that I was 'a hard marker'. That was just after a student had asked me, on receipt of his results, 'do you ever fail anyone'! I am not sure where the difference between us is re the third part. My formula for Ta is just the same as yours, except that I have expressed it slightly differently due to the limits of the keyboard. The formula for Tb was necessary because without that, you do not have Ta or Tb. You have come at it a slightly different way to how I did, but the result is the same. Full marks, and an 'Excellent Work' for it! Lloyd

I will be interested to know the results of your comparison. Re transition curves, I might have a spreadsheet that does that already for roads. I produced it for my use in marking Highway Engineering exams. I was a great help to me to identify where they had gone wrong! With regard to Chamby's comment about looking along the curve to check that it is smooth, reminds me of my road setting out days, where we would calculate the appropriate setting out data, and then set out with steel tapes (fibre tapes stretch - not as accurate) and theodolite reading to at least 20 seconds if not 5 or 1 second accuracy, so that it should have been spot on. ( an angle of one second gives an offset of about 1mm at 100 metres!) Then we looked round the curve that we had set out and adjusted it for smoothness by eye! These days they normally use GPS for setting out - supposed to be accurate to within a couple of mm. I'm sure that the old hands especially still eye it in for final adjustments. Lloyd

I was assuming that you were joining two arc curves together with a straight. If you are trying to join two curves, one or both being transition curves, that is a lot more complicated, and depends on the type of transition curve selected. If i had the time, I could try to work that one out for you for a specific case, but I had rather not try it, today especially, as I am helping my son move house today. Lloyd

You could calculate it if you prefer. If you know the distance between the curve centres, D, and the radius of each curve, Ra & Rb, then the common tangent will cross the line between the two centres at a point a distance Db from the centre of the curve radius Rb. That distance can be obtained from Db =D/(1+(Ra/Rb)) and the distance of this point from the tangent point on curve radius Rb, Tb, will be obtained from Tb = Sq Rt of ((Db*Db) - (Rb*Rb)) Ta = (Ra*Tb)/Rb I have just produced an excel spreadsheet to do the calculations for you. Just change D, Ra and Rb to what you want, and the rest should change automatically. Lloyd Setting out tangent between two curves in opposite directions.xlsx

Exactly! Lloyd

Strictly it would be transition curves between the two arcs, but the difference between that, a straight arc and a reverse curve would be minimal. Lloyd

Nothing of his to match a B1. Lloyd

Looks useful. As you say, much easier to get a tangent from the outside of the curve rather than the inside, and your tool should do the trick nicely. Lloyd

When it comes to most successful passenger loco, though the L1s were short lived and had a few problems, i would still plump for them as most successful Thompson design. Lloyd

Has to be Black 5 for me as well. Large class, though with a few variations, and excellent workhorses. My strongest memory is of a rail tour in about 1963-5 about. 70047 failed going north at Tebay (I think), by which time it was about an hour late. 45082 was commadered for the run onto Carlisle. Touched 82 downhill from Shap. Journey back to Crewe via Leeds meant last train to Derby had left, so stoke train extended to Derby for 6 of us. i then spent about 3 hours at Trent station waiting for a Nottingham train. That was also the only time I saw yesterday's favourite, the pacifics. They were in store at Upperby shed having been withdrawn. We disembarked from the train just opposite the shed. presumeably the adjacent line had been blocked. Lloyd

Strictly speaking, though the whole of Ireland was in the UK, it was not part of Britain. Hence you still get 'The United Kingdom of Great Britain and Northern Ireland'. However, I agree to adding it to the list as a UK engine. Just don't want to upset the Irish.

I am not a great fan of SR, but this is a difficult choice. Q1 aka flying dustbins, they did what they were designed for well as far as I can tell, and were a good example of an austerity design, but the appearance was pure engineering without any artistry. Merchant Navies, they appeared quite successful after having been rebuilt. Light pacifics, quite a number where not rebuilt, and they did useful work, though such a large engine for short trains did look like overkill. Class 12 shunters, lasted longer than any of the other designs doing useful work as far as I know, and I would guess formed the basis of the later class 08 shunters. CC1/2 again had quite a long life, performing valuable work, and presumably helped in the development of the later DC electrics. DD emus was a good idea, but getting in and out took too long for use as they were intended. As for his other emus, I don't know enough about, though they appeared to last a long time. I am split between the Q1 and Class 12, but I think I will go for the Q1. Lloyd

From the word's construction, either a little usher or a female usher (or would that be an usherene?). Next question - what's an usher. Someone who ushes. From that presumably an usherette is a little man that tells you to shut up! Oh. Someones going to do that to me now. Lloyd

Sorry to hear this. Hope it is not too uncomfortable. Lloyd

Perhaps an even better view of unsuccessful launches? Lloyd

What about a Space Port? I'm going to get a rocket for this. Lloyd

I know that I am! Lloyd