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All across the Great Western territory / Media about railways, and other means of transport / Re: Trainspotting Live - three part documentary on BBC4, 11 - 13 July 2016
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on: July 13, 2016, 12:12:41
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Also, was it me or did somebody say they had spotted a class 155 at Swindon? If so, was there really one (and if so why) or was it a slip of the tounge, or a novice trainspotter mistaking a pair of 153s for a 155?
I thought, but may well be wrong, they were talking about class 150s at Swindon but can't sure. Pulling into Maidenhead last night on the Bourne End train, there was a SouthWest trains' DMU▸ which had stopped just short of the platform on the down relief (I don't know what class it was).  It had a headboard of sorts but I thought this was very out-of place. I wonder if this was designed to go through Swindon when this programme aired ? |
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Journey by Journey / London to Reading / Re: Caroline
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on: May 25, 2016, 12:12:59
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Wouldn't that be a tad unusual for route knowledge?
I'll try and see where she went, must have been somewhere unusual.
Certainly rare to see southern stock in PAD» .
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Journey by Journey / London to Reading / Re: Caroline
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on: May 25, 2016, 11:25:16
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For the Gricers...975025. Caroline being a Southern Region Observation Saloon being propelled by a very smoky DRS▸ 37 on p11. Any reason why she was at P11 in PAD» ? |
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All across the Great Western territory / The Wider Picture in the United Kingdom / Re: Electricity - an ongoing technical discussion
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on: April 20, 2016, 14:39:47
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Would require a rather expensive transformer to step down 25KV to 230 or 115 volts to power the fairy lights.
And they would dim whenever a train went past, because the nominal 25KV supply varies a lot more than does the normal domestic mains.
A regulated power supply could be used. Transformer intended for 33KV input, so as not to be overstressed when the nominal 25KV approaches 33KV. Nominal 240 volt output, which might average nearer 200 volts actual. Then a switched mode power supply that accepts from 90 volts up to 270 volts AC input, regulated output of 12 volts DC▸ to the lights.
I hadn't realised that 25 Kv varied by too much around a 25Kv level. How much does it wary by? I presume there would be some sort of voltage thingy on board loco's to regulate the voltage back to a constant level for traction motors. The National Grid tries to keep the voltage constant, but varies the frequency, does something similar happens here ? W.E |
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Sideshoots - associated subjects / Heritage railway lines, Railtours, other rail based attractions / Re: Newly restored "Flying Scotsman" back in service - ongoing discussion
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on: February 26, 2016, 16:15:58
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'Soft' means the exhaust wafts out of the chimney rather than being forced out by a strong draught. Without smoke deflectors, smoke hangs around the boiler and cab reducing the crew's forward vision. The smoke deflectors do just what they say - they produce a draught that lifts the smoke up and away.
The single chimney had a stronger draught, hence no need for smoke deflectors.
It's a safety thing. I'd keep them on!
A soft exhaust also means that more work is done in the cylinder which then moves the wheels. Boiler pressure is about 225 lbs sq Inch, and exhaust pressure might be 20lbs, whereas with a single chimney the exhaust pressure may be 50lbs. Hence the double chimney increases efficiency, which is a damn good thing as its only about 5-8% at its very best. Lots of kettles were treated to double chimneys in the 50's in a forlorn attempt to extend the life of steam...... Quite like it in Brunswick green, in the Pegler / McAlpine years it was in Apple Green which is how many people remember it who would have been in their 50,60,70's. W.E
Edit note: Quote marks fixed, for clarity. CfN. |
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