eightf48544
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« Reply #2040 on: August 24, 2013, 09:11:10 » |
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One slight problem I've heard about teh "Freight Line" is due its gradient and curvature it is unlikely even a 59 could restart a heavy stone train if stopped by signals. So freight trains will nee a clear run from Reading West into the station.
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Gordon the Blue Engine
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« Reply #2041 on: August 24, 2013, 12:57:23 » |
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I think you're right. Mainly freight but not only freight on the reversible line you describe. But you can see a not uncommon situation, for example, where they want to start or changeover a Newbury stopper, and the easiest way to get a set to/from the depot is to use P12-15 and the "freight only" reversible.
I remember at one of the early roadshows in Reading this line was described as "freight only", and I questioned that at the time. Clearly it will not be freight only.
Are you remembering that both feeder lines, despite their names, are now to be connected to the relief lines? There's an extra set on points on the line to P12, not on the plan Paul posted above, as explained by SandTEngineer here http://www.firstgreatwestern.info/coffeeshop/index.php?topic=6405.msg131258#msg131258. I'm not sure what the thinking here is, but it did occur to me that you can't stop and wait on a reversible line - especially for something that's coming the other way on it. The extra connection gives the option of using the two "reversible" lines as a pair. So, not "freight only" and not always bidirectional either? I'd forgotten about you pointing out the apparent extra connection between P12 and the Up feeder line which is not shown on the "old" track diagram which Paul referred to. Has anyone got access to an updated track diagram for the final layout to the west of the station? Also, details of the points layout around Oxford Road Junction would be interesting, to see what operating flexibility that would offer.
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Gordon the Blue Engine
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« Reply #2042 on: August 24, 2013, 13:06:37 » |
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I One slight problem I've heard about teh "Freight Line" is due its gradient and curvature it is unlikely even a 59 could restart a heavy stone train if stopped by signals. So freight trains will nee a clear run from Reading West into the station.
Interesting to compare with the new Acton layout, where the freight lines into the yard will be kept relatively flat, and it's the passenger lines that go up and down. As well as the gradient and curve on the feeder lines, there may also be railhead condition issues, what with being in Reading town centre and being next to the depot sidings, with maybe idling diesel engines nearby. Anyone know what the max gradient on the feeder lines will be?
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SandTEngineer
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« Reply #2043 on: August 24, 2013, 15:09:37 » |
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Anyone know what the max gradient on the feeder lines will be?
According to the signalling plan the main lines rise and fall 1 in 93 over the new flyover with the lines underneath falling and rising approximately 1 in 90. Note: There is a general falling gradient from Reading station towards Tilehurst.
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Gordon the Blue Engine
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« Reply #2044 on: August 24, 2013, 18:26:21 » |
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So the 1 in 90 will become the new ruling gradient for Up stone trains from Westbury - not very clever that this is being installed as part of a route upgrade especially at a location where Red signals can be expected. I notice that Train 747K (a Whatley - Acton stone train) can load up to 4,800 tonnes. Up a 1 in 90 this requires a theoretical drawbar pull (not allowing for rolling resistance etc) of some 53 tonnes, or 119,000 lbf, rather more than a Class 59 can deliver even if it can get the adhesion. And that's before you take account of the effect of the curve and cant on rolling resistance.
So these stone trains will need Green signals from before Oxford Road Junction so they carry speed and momentum along the feeder line and up into the station, which will not be good for other trains around at the time.
Or maybe they'll be put though P7, and avoid the so-called "freight only" feeder line completely. Now that would be ironic!
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grahame
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« Reply #2045 on: August 24, 2013, 19:02:27 » |
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I notice that Train 747K (a Whatley - Acton stone train) can load up to 4,800 tonnes. Up a 1 in 90 this requires a theoretical drawbar pull (not allowing for rolling resistance etc) of some 53 tonnes, or 119,000 lbf, rather more than a Class 59 can deliver even if it can get the adhesion. And that's before you take account of the effect of the curve and cant on rolling resistance.
We seems to have solved the adhesion to pull problem for passenger trains of various length by using powered vehicles along the length of the train which also carry the passengers. Perhaps the next generation of freight train will follow the same solution, thus keeping the pull to weight ratio pretty much the same no matter how long the train is. We went from locomotive hauled trains from Paddington (I'm told - it was before I got involved in these parts) to trains with locomotives at both ends, and we're moving on to units with traction distributed throughout in the case of 10 car trains. Freight's a bit behind - we've moved from locomotive at the front to locomotive at both ends in many cases, and the next step seems logical, doesn't it?
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Coffee Shop Admin, Chair of Melksham Rail User Group, TravelWatch SouthWest Board Member
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stuving
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« Reply #2046 on: August 24, 2013, 20:24:19 » |
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Back to canopies ... I see that having almost filled the space from the existing canopy to the gap in the rail, the next three sections have gone at the far end. To my surprise, I found that the sections were just parked next to each other - some touching, some not quite, but with no bolts holding them together and presumably not fixed to the rails. That's not so bad with two rails, but it would be scary if they do the same with P10/11. That looks rather precarious on its single rail even if you know it is bolted down.
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ironstone11
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« Reply #2047 on: August 24, 2013, 21:25:04 » |
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Back to canopies ... I see that having almost filled the space from the existing canopy to the gap in the rail, the next three sections have gone at the far end. To my surprise, I found that the sections were just parked next to each other - some touching, some not quite, but with no bolts holding them together and presumably not fixed to the rails. That's not so bad with two rails, but it would be scary if they do the same with P10/11. That looks rather precarious on its single rail even if you know it is bolted down.
Another three panels being unloaded this evening! If they leave a gap, i.e. don't work from an end, I don't see how they can raise the last ones into position. Perhaps they haven't thought of that?
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James
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« Reply #2048 on: August 24, 2013, 22:16:22 » |
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I sort of question the fact, why the mainline is a flyover with Freight trains that have to go up a gradient below the mainlines... Would have made more sense to design the main line beneath the Freight and Local Passenger Lines, than above it. Oh dear does that mean future problems for passenger trains if freight trains get stuck on the gradient, if thats the case what good planning that was hey. As people say good old british engineering Ironstone 11 give them time, i am sure once its done (incorrectly) someone will remark and say, did we do it right?
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Be smart and help one another, if the other is in need, just common curtisy
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stuving
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« Reply #2049 on: August 24, 2013, 22:25:41 » |
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If they leave a gap, i.e. don't work from an end, I don't see how they can raise the last ones into position. Perhaps they haven't thought of that?
Oh, I'm sure they have - and planned all the moves in minute detail. There's lots of possible ways to do it: - bring in a much bigger crane to the forecourt
- use the crane they have there, or a slightly larger one, but from outside the existing canopy. For example, on or over the track in P7-8, or on P7 (no canopy at the moment)
- jack them up and put them on stands
- something else I've not thought of, which is probably what they will do.
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ellendune
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« Reply #2050 on: August 24, 2013, 22:28:20 » |
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Adapting existing infrastructure to meet new requirements is seldom straightforward. The process of design is usually fraught with compromises that you would never make if you were designing the thing from scratch. However, we are where we are (as the saying goes) so we have to make the best of what we have.
The vertical alignment is so often dominated by te constrains of getting over or under certain roads or other constraints that a perfect alignment was never going to be possible. In this case we have a gradient that is not ideal for freight. However there is a solution. If that means there is a constraint some freights have to wait until they can be signalled through P12 then that is still better than waiting for a path across the main line which is what we have now.
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James
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« Reply #2051 on: August 24, 2013, 22:35:17 » |
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Adapting existing infrastructure to meet new requirements is seldom straightforward. The process of design is usually fraught with compromises that you would never make if you were designing the thing from scratch. However, we are where we are (as the saying goes) so we have to make the best of what we have.
The vertical alignment is so often dominated by te constrains of getting over or under certain roads or other constraints that a perfect alignment was never going to be possible. In this case we have a gradient that is not ideal for freight. However there is a solution. If that means there is a constraint some freights have to wait until they can be signalled through P12 then that is still better than waiting for a path across the main line which is what we have now.
Now that is a reasonable statement, however it feels that more time should have been spent, on delivering a better project, rather than a rushed job, but as you say its what we have that we have to live for, for the next what 30 40 years or so? I wonder what they will construct then, a floating Reading Station, with the below station part filled with water?
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Be smart and help one another, if the other is in need, just common curtisy
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Red Squirrel
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« Reply #2052 on: August 24, 2013, 23:15:39 » |
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I notice that Train 747K (a Whatley - Acton stone train) can load up to 4,800 tonnes. Up a 1 in 90 this requires a theoretical drawbar pull (not allowing for rolling resistance etc) of some 53 tonnes, or 119,000 lbf, rather more than a Class 59 can deliver even if it can get the adhesion. And that's before you take account of the effect of the curve and cant on rolling resistance.
We seems to have solved the adhesion to pull problem for passenger trains of various length by using powered vehicles along the length of the train which also carry the passengers. Perhaps the next generation of freight train will follow the same solution, thus keeping the pull to weight ratio pretty much the same no matter how long the train is. We went from locomotive hauled trains from Paddington (I'm told - it was before I got involved in these parts) to trains with locomotives at both ends, and we're moving on to units with traction distributed throughout in the case of 10 car trains. Freight's a bit behind - we've moved from locomotive at the front to locomotive at both ends in many cases, and the next step seems logical, doesn't it? From my layman's-with-an-engineering-background, this sounds like an interesting idea. If a standardised approach could be taken (and there, of course, is the rub) with each wagon containing its own modular power unit (we're talking electric-only here) then the 'locomotive' need consist of little more than a cab, supply pick-up and control module. But why not extend this concept to passenger stock? A complete reversal of the traditional loco-hauled train. Potentially this could also return some of the flexibility that was lost with the wholesale adoption of unit trains. A plug-and-play railway?
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Things take longer to happen than you think they will, and then they happen faster than you thought they could.
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stuving
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« Reply #2053 on: August 24, 2013, 23:20:33 » |
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There have been suggestions since years back that some urban rail systems could work with small single vehicles that can be routed point to point. I'm not sure how many have got very far. The two problems I know of are efficiency - it would help to join cars into trains for trunking - and safety, i.e. spacing, how to couple them etc. But the basic engineering is all quite doable.
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Oxman
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« Reply #2054 on: August 25, 2013, 01:22:31 » |
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I was once told by a signaller in the old Reading panel that, if at all possible, they would give a freight off the B&H▸ a clear run from Southcote Junction through the station to the up relief. The reason being that, if they stopped it, it would take so long to restart that the delays would be far greater than simply giving it a clear road. Thus the reason why so many down main class 1s were held at the old platform 4 whilst an up stone train was allowed across Reading West junction in front of them, and why all of this money is being spent to eliminate such conflicts. Its clear to me that the provision of a flyover/diveunder will make a huge difference, whatever the gradients, and whatever the need to give a clear run. The days of class 1s being held at Reading for an up stone train will be no more! Job done.
All so worth saying that the discussion on here about how things will be done ("I suppose it will all work out in the end") could not be further from the truth. Every operation will have been planned in the finest detail. In the offices of the former Post Office sorting office on Vastern Road, there is a large, multi-disciplinary team, consisting of engineers and planners from all of the parties (NR» , FGW▸ and all of the contractors) that has planned every step in minute detail. Every operation will have been walked though and risk assessed. There is a team of professionals at work here who, so far, have delivered ever stage on time and, according to NR, to budget. To suggest that "they haven't thought of that" or that this is a "rushed job" is, frankly, ridiculous.
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