Wright writes.....

[Tony Wright]

One side effect of scrambling around looking for something else has been the unearthing of several long-forgotten kits; one of which was a Kirk Gresley triplet catering set. 

 

This was started about 12 years ago by our elder son, Tom; before he 'lost' interest in model railways and began rebuilding twelve inches to the foot old cars. 

 

One of the things I noticed in taking still pictures and filming moving images for the 1938 Little Bytham weekend was the discrepancy in ride height and parallelism of some of the stock, particular articulated vehicles. There was so much discrepancy in one rake, that none of the images was used. Now, I know (from personal experience) that matching articulated stock can be very difficult, but I think I've found a workable (and easy) solution. 

 

 

 

This is my method of joining adjacent articulated cars. It's no more than thin brass etch (from the edge of a kit sheet), which (at one end) is adjustable for distance apart and for parallelism. The carrying bit is bent down ever so slightly to accommodate the thickness of the brass, and it's held in place by an 8BA bolt. The pivot is a 6BA bolt, soldered to the top strip. Bogies on this 1924 set are PC (these, at source, are actually heavy-duty in size, which they should be for artics). 

 

This is the first time I've used this system (have I invented it?), because I've never been entirely happy with how I've configured articulation in the past. 

 

 

PC bogies have been used throughout. To prevent rock, the bolster rides below a brass washer, rather than the plastic soleplate. Comet parts have been used to improve this set. I know it's still a thick-sided Kirky, but I've asked Geoff Haynes to paint it in full LNER teak livery when I've completed it (for service on Grantham?). On test this morning, the whole lot was absolutely rock-steady with no out-of-alignment issues at all. 

 

I don't need any more triplets, because I've got the following. 

 

 

A Comet triplet set (riding on PC bogies) which I built for review, a few years ago now.

 

 

The ex-Silver Jubilee triplet in post-War, later BR guise. I built this from a Mailcoach kit (not for the faint-hearted!). This one runs on MJT bogies - I don't use plastic bogies. This was also written up in BRM.

 

 

Finally, one of the ex-1938 Flying Scotsman triplets, seeing service in The Northumbrian (complete with standing bar). Again, another mentioned in BRM. John Houlden built most of this using Rupert Brown/MJT/Comet/Kirk parts, and I completed it, making the interiors as well. Geoff Haynes painted this one. 

Edited October 29, 2018 by Tony Wright

[Lecorbusier]

I’m struggling to get my head around this last question. The video evidence tends to relate to express engines slipping their wheels because few bothered to video goods trains pulling away.

 

I still think the physics indicates that a smaller wheel will be more likely to lose traction because the tractive force exerted at the rim is greater than that on a larger wheel for the same cylinder pressure whilst the coefficient of friction remains the same irrespective of diameter. That assumes everything else remains the same I.e. the same number of driven axles. Remember that an 8 coupled goods loco is distributing the forces exerted through the connecting rod across 8 wheels rather than 6 as in a typical express loco and so this will reduce the tendency for a goods locomotive to slip.

 

Of course in reality there are many variables at work including actual weight on each driven axle, the crank throw, the steam pressure as well as the wheel diameter and the number of driven axles, all of which will have an influence on the risk of wheel slip.

 

Frank

For those who might be interested ... I came across this summary penned by Will Litchfield on the Scalefour forum which I find explains things very well ....

 

 

 

Some may find this a bit like hard work. I have been deliberately vague about the units in play as the coefficient of friction is a unit less ratio and the same numbers work what ever unit's you chose. .

 

All this is bound up with the fact that there are two coefficients of friction between the wheel and rail that we need to consider. There is the static coefficient which applies when the wheel and rail are in contact but not moving one relative to each other, i.e. when the wheels are either standing still or rolling normally. Then there is the kinetic coefficient which applies when one is sliding over the other. The static coefficient is about 0.6 and the kinetic one is about 0.4 .

In either case multiplying the weight being carried by the coefficient gives you the maximum amount of force which can be transmitted through the wheel to rail contact point. You will notice that once a wheel starts to slip much less force can be transmitted.

 

It is easier to see what’s going on if we consider what happens if we try and push a loco along the track by applying a force to the coupling hook. Let’s say the loco has six wheels each carrying a weight of 50 and the wheels are locked solid by the motor and can’t turn. The applied force will be along the vehicle centre line and parallel to the track, so a moments thought about moments will tell you that, all else being equal, the force will be equally divided between the six contact points between wheel and track. The maximum force that can be resisted by each contact point before it begins to slide is given by multiplying the weight by the coefficient of static friction which gives 30 (50*0.06) per wheel or 180 for the whole loco. This is directly equivalent to the loco trying to pull a weight along and the 180 is the maximum force the loco can exert to pull a train before it will start to slip.

 

Going back to pushing the loco, once that 180 force has been exceeded and the chassis starts to slide the kinetic coefficient will apply. This is smaller than the static coefficient (0.4 as against 0.6) which means that less force is required to keep it sliding (thats 6*50*0.4 or 120) than it took to start it (180). This is the reason why it is harder to start something sliding than to keep it going when it is sliding and why, once all the wheels on a loco pulling a train starts to slip, it must reduce power significantly to stop slipping.

 

Ok now let’s assume that our loco has the same overall weight of 300, but it is now distributed unequally across the wheels. Let’s say 40 on two wheels and 55 on the other 4. When we try and push the loco, once the force per wheel exceeds he maximum force transmissible by the lightly loaded wheels, that's 24 per wheel (40*0.6) or 144 overall. Those two wheels will start to slip, and once that happens the kinetic coefficient applies and their contribution to resisting the force drops to 16 (40*0.4). The forces in excess of this will automatically and suddenly transfer themselves to the wheels that are not yet slipping. The shock of this may be enough to start all the wheels slipping, and if that happens it will keep on sliding until the pushing force drops below 120. 

 

Even if the other 4 wheels do manage to hang on in there, the lightly loaded wheels can’t transmit their full share of the load and so will always be on the cusp of slipping. As a result they can’t reliably transmit any more than the 16 permitted by the kinetic coefficient. When the other 4 reach their limit at 33 (55*0.6) they will slip too giving a maximum force before slipping starts of 164 (that’s 4*33 plus 2*16). Net result this chassis may slip at a force of 144 or struggle on to reach 164. Compare that to the 180 when the wheels were equally loaded. 

 

Again what applies to pushing the chassis with locked wheels apples equally to a the chassis under power pulling a train.

Ok this is all a bit of perfect world stuff but you see the way the wind is blowing. The fact that the wheels are coupled together doesn’t change things, particularly as they aren’t that rigidly couples and are capable of small amounts of movement relative to each other.

[Barry Ten]

Setting aside the prototype, I've found that adhesion in model terms can be quite counter-intuitive.

 

This DMU, for instance, was initially fitted with a single Black Beetle bogie and couldn't pull the skin off a rice pudding, barely

managing to move itself, even with a lot of weight over the driven bogie:

 

 

On the other hand, this Blue Pullman power car has two BBs and despite being only lightly weighted has ample adhesion for another 7 cars, plus plenty in reserve:

 

 

OK, two BBs in one unit will make a difference, but I couldn't understand why the DMU was so underpowered whereas the Blue Pullman was easily capable of moving itself around. The only difference in the BBs was wheel diameter, 12mm in the case of the DMU and 14 in the BP. In the end, I removed the 12mm wheels from the DMU unit and substituted Bachmann 14mm coach wheels instead. That was all it took, with the DMU now being much happier, now being well capable of moving itself. The original BB wheels are quite fine in profile so in addition to an extra 2mm of diameter, the Bachmann wheels have a deeper rim (therefore more contact area?) but I'm still surprised at the difference.

 

I've also got a Lima Western running on Ultrascale wheels, so that's just two driven axles without traction tyres, but it's a surprisingly good hauler - but again, the wheel diameter may be the clue.

 

Al

 

ps - sorry for these pictures being large, something to do with linking to them from the blog area.

 

 

 

 

[Headstock]

For those who might be interested ... I came across this summary penned by Will Litchfield on the Scalefour forum which I find explains things very well ....

 

Afternoon LCB,

 

The same applies to real locomotives, I've worked out a number of 'adhesive factors' for different locomotives that confirm anecdotal evidence of the different performance characteristics of different locomotives. For example, why did the Thompson Pacific succeed on the heavy Concrete trains while the 9F's failed, yet the former had a reputation for slipping? Why were the V2's so effective at starting 26 carriage trains during the war? I don't have time to post at the mo but I think that you will find the following of interest.

 

Adhesion is caused by friction, with maximum tangential force produced by a driving wheel before slipping given by:

F_max= coefficient of friction × Weight on wheel^[2]

Usually the force needed to start sliding is greater than that needed to continue sliding. The former is concerned with static friction, referred colloquially to as "stiction", or "limiting friction", whilst the latter is dynamic friction, also called "sliding friction".

For steel on steel, the coefficient of friction can be as high as 0.78, under laboratory conditions, but typically on railways it is between 0.35 and 0.5,^[3] whilst under extreme conditions it can fall to as low as 0.05. Thus a 100-tonne locomotive could have a tractive effort of 350 kilonewtons, under the ideal conditions (assuming sufficient force can be produced by the engine), falling to a 50 kilonewtons under the worst conditions.

Steam locomotives suffer particularly badly from adhesion issues because power delivery is pulsed (especially in 2- or most 4-cylinder engines) and, on large locomotives, not all wheels are driven. The "factor of adhesion", being the weight on the driven wheels divided by the theoretical starting tractive effort, was generally designed to be a value of 4 or higher, reflecting a typical wheel-rail friction coefficient of 0.25. A locomotive with a factor of adhesion much lower than 4 would be highly prone to wheelslip. Other steam locomotive design factors significantly affecting traction include wheel size (smaller diameter wheels offer superior traction at the expense of top speed) and the sensitivity of the regulator.

[Manxcat]

Tony,

Would there be any possibility of seeing a couple of close up photos of one of the ground signals on LB please? I am particularly interested in how they are operated and the linkages to the disc that make the movement happen. Thanks.

Archie

[micknich2003]

Are these of any use

?

[Tony Wright]

Tony,

Would there be any possibility of seeing a couple of close up photos of one of the ground signals on LB please? I am particularly interested in how they are operated and the linkages to the disc that make the movement happen. Thanks.

Archie

They're covered in my Crowood book, Archie.

 

But I'll see if I've got other pictures as well. They're made from MSE kits.

 

Almost all of them work now, with just four or so in the layout's centre to be made operational The reason Roy Vinter (who made the signals) and I are holding back a little (other than because installing the mech's cripples our ageing knees!) is because those mech's will have to be fitted through a veritable forest of wires, running from the four controllers. Not only that, there's also a fan of wires spreading out from the point/signal power feeds which will need negotiating. I don't know about you, but whenever wires are disturbed (no matter how well they've been soldered on to tag strips or point/signal contacts) there's always the risk of their failing. At the moment (tempting fate, of course), all those wires are functioning perfectly, and I'm reluctant to compromise that. That said, the operation of the little ground discs always causes great interest among visitors. Four who visited this morning were delighted. 

 

Regards,

 

Tony.

[Tony Wright]

Thank you all for the further comments on coefficients of friction and haulage powers, etc, (though I might have been more 'convinced' of the Litchfield piece had the grammar been better).

 

I have to say, and this is entirely personal, almost all of what's been written about this goes right over my head (I admit, I'm dim). In my own case (though knowledge, I acknowledge, is power), I apply not one of those cerebral messages to the locomotives I build.

 

What do I do? I build each model loco with a view to what it might be expected to pull. That's not to say a smaller 0-6-0 could not pull, say, The Elizabethan on LB, but clearly it wouldn't happen. A small 0-6-0 (in reality) might easily be capable of moving the empty stock, but not be able to average 60 mph for nearly 400 miles. 

 

When I've built a loco (actually, before all the motion is on), I'll test it on the heaviest train it might be expected to haul - 15 kit-built bogies. If the loco is mainly made of white metal, and it shifts such a load with (relative) ease (I quite enjoy a bit of slipping on starting), then I'll leave it at that; perhaps adding a little lead. If it's a brass/nickel silver one, I pack every nook and cranny with lead, either in 'fluid' form or sheet. 

 

Model loco haulage capacity is all to do with weight in my experience. All my locos have the necessary adhesive weight to do their duties. (bogies and ponies, not being sprung, carry just their own weight). I'm not saying the 'science' behind it doesn't interest me, but it's of no practical use as far as I'm concerned. Being a Luddite, I know what works. What works for me, of course. 

 

And, it's weight (or lack of it) which militates against RTR locos (with few exceptions - Bachmann 9Fs, for instance). Because such locos (which I have) have mainly plastic bodies, they're just too light for what I might ask of them. There's also (usually) little room inside to add more ballast. 

[Tony Wright]

Afternoon LCB,

 

The same applies to real locomotives, I've worked out a number of 'adhesive factors' for different locomotives that confirm anecdotal evidence of the different performance characteristics of different locomotives. For example, why did the Thompson Pacific succeed on the heavy Concrete trains while the 9F's failed, yet the former had a reputation for slipping? Why were the V2's so effective at starting 26 carriage trains during the war? I don't have time to post at the mo but I think that you will find the following of interest.

 

Adhesion is caused by friction, with maximum tangential force produced by a driving wheel before slipping given by:

F_max= coefficient of friction × Weight on wheel^[2]

Usually the force needed to start sliding is greater than that needed to continue sliding. The former is concerned with static friction, referred colloquially to as "stiction", or "limiting friction", whilst the latter is dynamic friction, also called "sliding friction".

For steel on steel, the coefficient of friction can be as high as 0.78, under laboratory conditions, but typically on railways it is between 0.35 and 0.5,^[3] whilst under extreme conditions it can fall to as low as 0.05. Thus a 100-tonne locomotive could have a tractive effort of 350 kilonewtons, under the ideal conditions (assuming sufficient force can be produced by the engine), falling to a 50 kilonewtons under the worst conditions.

Steam locomotives suffer particularly badly from adhesion issues because power delivery is pulsed (especially in 2- or most 4-cylinder engines) and, on large locomotives, not all wheels are driven. The "factor of adhesion", being the weight on the driven wheels divided by the theoretical starting tractive effort, was generally designed to be a value of 4 or higher, reflecting a typical wheel-rail friction coefficient of 0.25. A locomotive with a factor of adhesion much lower than 4 would be highly prone to wheelslip. Other steam locomotive design factors significantly affecting traction include wheel size (smaller diameter wheels offer superior traction at the expense of top speed) and the sensitivity of the regulator.

Thanks Andrew,

 

Though I'm totally baffled (naturally).

 

May I please point out that it was a cement train which only the Thompson A2/3s were able to time up Stoke Bank, not concrete?

 

Regards,

 

Tony. 

[Lecorbusier]

(though I might have been more 'convinced' of the Litchfield piece had the grammar been better).

 

More convinced? ... or more happy to be convinced? .... I submit that communication leading to understanding may well be at times no respecter of grammar, but valuable none the less. 

[Tony Wright]

 

(though I might have been more 'convinced' of the Litchfield piece had the grammar been better).

 

More convinced? ... or more happy to be convinced? .... I submit that communication leading to understanding may well be at times no respecter of grammar, but valuable none the less. 

 

Thanks Tim,

 

This sort of thing has come up before (and has been discussed at length),

 

I concede that, as long as the 'message' is easily understood, then, to some extent, grammar is irrelevant. However, if one is submitting a piece for a learned journal, might it have even more 'impact' if possessive apostrophes are present where they're needed, and not present where they're not? And an understanding that 'between' can only mean between two things and not among (or amongst for those who prefer that) more than two? 

 

I'm reminded in my teaching days of how grammar could be all important. When questioned about a broken window, one little miscreant told me 'I didn't do nothing, Sir!' I thanked him for his owning up!  

 

Regards,

 

Tony. 

Edited October 29, 2018 by Tony Wright

[Headstock]

Setting aside the prototype, I've found that adhesion in model terms can be quite counter-intuitive.

 

This DMU, for instance, was initially fitted with a single Black Beetle bogie and couldn't pull the skin off a rice pudding, barely

managing to move itself, even with a lot of weight over the driven bogie:

 

 

On the other hand, this Blue Pullman power car has two BBs and despite being only lightly weighted has ample adhesion for another 7 cars, plus plenty in reserve:

 

 

OK, two BBs in one unit will make a difference, but I couldn't understand why the DMU was so underpowered whereas the Blue Pullman was easily capable of moving itself around. The only difference in the BBs was wheel diameter, 12mm in the case of the DMU and 14 in the BP. In the end, I removed the 12mm wheels from the DMU unit and substituted Bachmann 14mm coach wheels instead. That was all it took, with the DMU now being much happier, now being well capable of moving itself. The original BB wheels are quite fine in profile so in addition to an extra 2mm of diameter, the Bachmann wheels have a deeper rim (therefore more contact area?) but I'm still surprised at the difference.

 

I've also got a Lima Western running on Ultrascale wheels, so that's just two driven axles without traction tyres, but it's a surprisingly good hauler - but again, the wheel diameter may be the clue.

 

Al

 

ps - sorry for these pictures being large, something to do with linking to them from the blog area.

 

Evening Al,

 

I like your large pictures, the detail and the colouration looks fantastic.

[Lecorbusier]

Thanks Tim,

 

This sort of thing has come up before (and has been discussed at length),

 

I concede that, as long as the 'message' is easily understood, then, to some extent, grammar is irrelevant. However, if one is submitting a piece for a learned journal, might it have even more 'impact' if possessive apostrophes are present where they're needed, and not present where they're not? And an understanding that 'between' can only mean between two things and not among (or amongst for those who prefer that) more than two? 

 

I'm reminded in my teaching days of how grammar could be all important. When questioned about a broken window, one little miscreant told me 'I didn't do nothing, Sir!' I thanked him for his owning up!  

 

Regards,

 

Tony. 

Agreed .... though of course a 'learned journal' will be subject to a process of proof reading both by the author and editor followed by a dedicated proof reader .... A forum response has no such safeguards or back-up. I gained much from Will's explanation and am minded to forgive the errors which I am certain were not intentional.

[vitalspark]

Tony,

Would there be any possibility of seeing a couple of close up photos of one of the ground signals on LB please? I am particularly interested in how they are operated and the linkages to the disc that make the movement happen. Thanks.

Archie

 

Will send you a mail Archie with details of our working discs.

For Larbert they are LMS pattern of course.

We use Palatine etches which are dead scale and work well with minor modification.

 

Dave. 

[Tony Wright]

For those who don't have my Crowood book and who wish to know a little bit about the operation of LB's little ground discs, may I present the following pictures, please?

 

 

Mick Nicholson very kindly supplied us with a signalling diagram of the period for LB. One of the made-up signals is present in this shot, and the basic operating mechanism. Both the work of Roy Vinter.

 

 

Here's one of the operating mechs installed beneath the baseboard. It works on the principle of being pulled 'off' by pulling a piece of cotton, returning to 'on' by gravity.The copper paddle is adjustable and extra weight can be added, if necessary, to the end of the brass lever. 

 

 

Ray Chessum came up with the idea of how to operate the signals from the baseboard edge (thanks again to all those who donated GEM point levers). Aren't I lucky to have such able ground signal-making friends?

 

 

The rounded wooden support prevents belly-injuries!

 

 

 

Two of the signals in situ. I really need to make some representation of the above-ground operating equipment. 

 

 

I'm very fortunate to have had my main line signals made for me; by Mick Nicholson and Graham Nicholas. Graham installed all the Wiessman (is that the correct spelling?) operating motors as well. 

 

 

 

I'm equally fortunate to have had Tony Gee make (and make work) my MR/M&GNR signals. The LNER loco and BR train scene is anomalous, I know. 

 

As much as any moving train, signals (particularly semaphores) animate a layout. Non-working signals? As I've said before, not so good! 

 

 

 

 

 

 

[St Enodoc]

For those who don't have my Crowood book and who wish to know a little bit about the operation of LB's little ground discs, may I present the following pictures, please?

 

Signals 12.jpg

 

Mick Nicholson very kindly supplied us with a signalling diagram of the period for LB. One of the made-up signals is present in this shot, and the basic operating mechanism. Both the work of Roy Vinter.

 

Signals 13.jpg

 

Here's one of the operating mechs installed beneath the baseboard. It works on the principle of being pulled 'off' by pulling a piece of cotton, returning to 'on' by gravity.The copper paddle is adjustable and extra weight can be added, if necessary, to the end of the brass lever. 

 

Signals 14.jpg

 

Ray Chessum came up with the idea of how to operate the signals from the baseboard edge (thanks again to all those who donated GEM point levers). Aren't I lucky to have such able ground signal-making friends?

 

Signals 15.jpg

 

The rounded wooden support prevents belly-injuries!

 

Signals 16.jpg

 

Signals 17.jpg

 

Two of the signals in situ. I really need to make some representation of the above-ground operating equipment. 

 

Signals 04.jpg

 

I'm very fortunate to have had my main line signals made for me; by Mick Nicholson and Graham Nicholas. Graham installed all the Wiessman (is that the correct spelling?) operating motors as well. 

 

BRM LB 13 B12 on Leicester.jpg

 

D16 3 weathered.jpg

 

I'm equally fortunate to have had Tony Gee make (and make work) my MR/M&GNR signals. The LNER loco and BR train scene is anomalous, I know. 

 

As much as any moving train, signals (particularly semaphores) animate a layout. Non-working signals? As I've said before, not so good! 

Very nice Tony. All you need now is an interlocked Modratec lever frame to connect them all to....

[MJI]

9F and A2.

 

I think I would be right in saying that a 9F could pull more but on a load within the A2 it would pull faster.

 

9F can shift 2000 ton but on less weight an A2 would out run it.

 

That is right isn't it?

 

(My favourite steam locos are 9F then Castles)

[Manxcat]

Are these of any use

?GROUND DISC Cherry Tree 1983.jpg

LNER DISC from rear.jpg

LNER DOUBLE DISC 2.jpg

TRACKWORK 877.jpg

 

Prototype Photos! Thank you.

[AndyID]

Hi Tony,

 

The grammar is a bit suspect, as is the technical description However, leaving aside real locomotives and concerning ourselves with models, the number of wheels does not matter, and that's why your rigid chassis models work just as well, if not better, than models with suspension.

 

Your track is really good, but it cannot be perfect, and when a driver starts to lose contact with the rail the weight of the locomotive has to go somewhere so it is distributed across the other wheels. That increases the contact pressure between those wheels and the rails and that increase their friction with the rail. Accordingly the total friction remains the same. And that's the wonderful thing about friction. It's only the weight that matters. The number of contact points and/or contact area has nothing to do with it at all (counter-intuitive perhaps, but absolutely true).

 

(Should there be any grammatical or spelling errors in this post I should point out that, according to my blazer badge, I went to a gramar school.)

 

Cheers,

Andy

[Manxcat]

Thank you Tony. I should have looked in your book first. What a very good set of follow up photos. 

 

Thank you too, to vitalspark, a good friend of mine who sent me photos of the ground signals he is making for his group's Larbert layout.

 

The response to my question once again reinforced my continuing delight in the helpful way so many on this thread will respond to a simple question. 

 

Archie

[Headstock]

Thanks Andrew,

 

Though I'm totally baffled (naturally).

 

May I please point out that it was a cement train which only the Thompson A2/3s were able to time up Stoke Bank, not concrete?

 

Regards,

 

Tony. 

 

Thanks for the correction Tony,

 

concrete, cement, equally baffled apparently.

Edited October 29, 2018 by Headstock

[bbishop]

Tony,

 

The correct spelling is Viessmann.

 

Bill

[Headstock]

9F and A2.

 

I think I would be right in saying that a 9F could pull more but on a load within the A2 it would pull faster.

 

9F can shift 2000 ton but on less weight an A2 would out run it.

 

That is right isn't it?

 

(My favourite steam locos are 9F then Castles)

 

The A2 is all round the more powerfull locomotive, bigger boiler and firebox, greater steam production capacity, bigger drawbar pull, higher tractiffe effort, and pherhaps most suprisingly for many, a better adhesive factor.

[jwealleans]

May I please point out that it was a cement train which only the Thompson A2/3s were able to time up Stoke Bank, not concrete?

Did anyone with a sense of humour ever roster the concrete brake van onto it?

[Tony Wright]

9F and A2.

 

I think I would be right in saying that a 9F could pull more but on a load within the A2 it would pull faster.

 

9F can shift 2000 ton but on less weight an A2 would out run it.

 

That is right isn't it?

 

(My favourite steam locos are 9F then Castles)

Martin,

 

As far as I'm aware, the A2/3 is a much more powerful loco than a 9F. The boiler and firebox are considerably bigger, and the weight (101 tons 10 cwt, A2/3, 86 tons, 14 cwt, 9F) a lot more. Tractive effort for an A2/3 is quoted as 40,430 lb for the A2/3 and 39,670 for the 9F (I've always been a bit suspicious of quoting tractive effort as a measure of power, because, according to that, a K4 is more 'powerful' than an A4!). Still, according to tractive effort the A2/3 and the A2 have the highest of any 8P class. 

 

It was Peter Townend who writes that he suggested an A2/3 be put on the cement block train (the heaviest train on the ECML at the time), though Dave Somers reckons that it was his dad, Jack Somers, shedmaster at New England, who actually thought of the idea. At a stroke, time was no longer lost up Stoke Bank. V2s (even those with double chimneys) lost time, as did the 9Fs. 

 

A fitting epitaph for Edward Thompson? One of his Pacifics was the best at hauling a cement train. 

 

Regards,

 

Tony. 

Edited October 29, 2018 by Tony Wright