Preserved railways' train lengths

[sprinterguy]

This is a thought I've had for a while, but having been knocking about the Severn Valley Railway today it's been refreshed in my mind:

A lot of the major preserved railways, the SVR, NYMR, etc, operate trains of load 8 or load 9 mark 1s, which easily adds up to 300 tonnes when you add passengers. And I was looking at some of the little 2-6-2Ts and there ilk that haul these formations, and I know the GWR small Prairies were renowned for their power, but they seem a bit lacking for a 300 tonne load 9 train!

So I'd be interested to know if anyone knows what the maximum allowed train weights various steam locos classes were in normal everyday service in steam days?

If these weights are exceded on the preserved lines, and I suspect some are, how is this managed? Is it because the lower 25mph speed of preserved lines is less taxing on the locos and such train weights are therefore possible for small locos? Some lines, and the North York Moors' 1 in 49 comes to mind here, have quite severe gradients, and it sometimes surprises me the train loads that various locos manage to haul up these climbs.

 

[ralphchadkirk]

Interesting question. I'll ask around about that.
On my local railway the maximum length is 6 coaches (pax) due to limitations in signalling.

 

[Vulcan]

On the Abbey Light Railway its 3 coaches, mainly because we only have 3 coaches.

 

[4SRKT]

At the K&WVR it's 6 coaches because the loop at Damems can't take any more. The only time I've ever seen 2 6-coach rakes operating is on enthusiasts' weekends though. More typically there's a main train featuring the buffet car, which is 5 or 6 coaches, and on summer Sundays an extra set of 3-5 coaches. They make extensive use of the old Kings Cross outer suburban coaches, which at 57' and no corridor connections must be substantially lighter than a normal mk I.

 

[sprinterguy]

On the Abbey Light Railway its 3 coaches, mainly because we only have 3 coaches.

Only having three coaches is quite a major limiting factor on train length

I've been reading O.S. Nock books recently, and some of the maximum train weights quoted for big locos, such as the Black Fives, on the more challenging routes, suggest that just over 400 tonnes was considered a match for such a loco: Which has fuelled my curiosity when looking at the loads class 2 and 3 tank locos are handling on the preserved lines.

 

[E&W Lucas]

If these weights are exceded on the preserved lines, and I suspect some are, how is this managed? Is it because the lower 25mph speed of preserved lines is less taxing on the locos and such train weights are therefore possible for small locos? Some lines, and the North York Moors' 1 in 49 comes to mind here, have quite severe gradients, and it sometimes surprises me the train loads that various locos manage to haul up these climbs.

Essentially yes. There's a lot of difference between taking the Mid Hants Alps at 25 vice 60, or Goathland bank at 17- 18 mph, rather than 35.

BR also tried to limit locos to loads that they could hopefully be guaranteed to restart at any point on a given route. Preserved lines do not always have that luxury, and have to use what is available.

 

[fsmr]

At the Stapleford 10 1/4" we have two 9 coach sets (about 55 pax per set)
We have run all 18 coaches with the NKP Berkshire and NYC Niagara double heading but it wont fit into the station on the return so not viable apart from specials
Our limit is the 1 in 50 climb up from the lake, probably akin to the Lickey in scale terms and just as testing on locos and driver (who also has to fire the loco and cant blame anyone else if it all fails!!)

The 4-6-0 Saint and 4-6-0 Jubilee have to double head to take 9 coaches up although they can handle 5 up the bank on their own when on private runs even full
The limit of course comes when it rains and lack of sanding equipment comes into play and even the 2-8-4 Berkshire and 4-8-4 Niagara loose their feet
Having air braked stock though removes any issues with braking performance versus locomotive braking

Agree with all the other points made, most preserved lines could get away with a small tank on schedules and timings never encountered in their former lives

Nige
www.fsmr.org.uk
www.youtube.com/stapleford

Here is me blasting up the 1 in 50 with nine on on the SMR Berkshire

 

[Vulcan]

8 seems to be the norm on the Beer Heights Light Railway. Not bad for 7 1/4" gauge!

 

[9K43]

A MK 1 Coach comes in at about 33 tons, and is approximately 3SLU's long.
If you have 12 on a charter 36SLU's.

 

[sprinterguy]

Hmmm, interesting, I've never thought about the load limits for trains on the narrower gauge railways, that's some fascinating facts. Which has me thinking, is the power of the narrow guage loco in proportion to the power of its' full size counterpart? Or does a narrow gauge engine have more or less power per "scale tonnage"?

Thinking in particular of the Stapleford example above, and that really impressive picture of the "Berkshire" loco (it still gives the impression of massive size despite it's narrow gauge), just how heavy are those nine open carriages, complete with a full compliment of passengers?

A MK 1 Coach comes in at about 33 tons, and is approximately 3SLU's long.
If you have 12 on a charter 36SLU's.

What's an SLU? Of the many acronyms on the railways, I've never heard of that one!

Another thought, the length of the trains on the major standard gauge preserved railways often hugely exceed the lengths of the platforms at intermediate stations (and at some of the termini too!), due to their previously being on branch lines handling no more than 3/4 carriage trains. I wonder, if the popularity of preserved railways was to continue to increase (more families with higher disposable income, enthusiasts who have better mobility than in the past and more spending money), if this would eventually become a problem with the loading and unloading times at intermediate stations? Though to answer my own question to an extent, the train lengths are at their maximum possible length now due to the lengths of passing loops, and preserved lines' passenger loadings are more constrained by the number of seats available (no standing) in comparison to the national network, so the number of passengers per train must be quite well regulated.

With my first question now answered, I'd still be interested to know if anyone has any idea of the typical workaday load limits from BR days for, say a GWR 57XX Pannier, or 2-6-2 Small Prairie, to compare with the loads they're handling at a more leisurely pace these days on the preserved lines.

 

[blackfive460]

What's an SLU? Of the many acronyms on the railways, I've never heard of that one!

Standard Length Unit

 

[Teaboy1]

Load limit or normal limit on the WHR tends to be 8 carriages but on weekend specials, they tend to add a few trucks for the occasion. The NG16's tend to be well on top of the job in the dry....... but the problem is with adhesion on wet rails and these Garratts do struggle to find their feet in wet tunnels or setting off from Campsite station on a 1:43 gradient. Obviously, a bit more weight would help as would the sanders (if ever they actually work??). North bound trains tend to fill the water tanks at Beggelert (1000 gal = 10 000 lb = 4.5 ton) and this may help but on a wet day/night in November, the Garretts are spinning most of the way upto the summit or setting off from a halt.
Platform length is very generous on WHR so I would logically assume that the limiting factor is worst case scenario, wet starts up hill, no sanders working!

Regarding TE, these NG16's are rated at 18 800 lb while a BR class 3T comes in with about 21 000 lb but if they have some Factor of Adhesion differences then Im lost, but the gauge is naturally less than half a class 3T. HTH

 

[fsmr]

Here is the SMR Berkshire again with a lightly loaded 5 coach on a very cold Feb 2010 early evening private members only train and yes it does look and sound big

close your eyes and you could be in the states in the 1940s still

[youtube]PmxzDtn0kMA[/youtube]


In response to the loadings questions on narrow gauge lines
with regard to Staplefords fleet, all ours are 1/5th scale apart from the EAR 31 which being metre gauge ends up at 1/4 scale. However although they run at scale express speeds, the air resistance is not really a factor, and so the locos are developing maximum power but with no real increase in load. The Loading at Stapleford is around 6 PAX per coach. Each open coach weighs around 300kg with bogies so if you say 60 kg for each PAX (and thats low!! that is another 360kg so all up of 660kg per coach. Normally we run at 9 coaches!! The Berkshire and tender weighs in at about 2,800 kgs if you want to compare loco weight to loads
Nigel

 

[E&W Lucas]

Regarding TE, these NG16's are rated at 18 800 lb while a BR class 3T comes in with about 21 000 lb but if they have some Factor of Adhesion differences then Im lost, but the gauge is naturally less than half a class 3T. HTH

You've just highlighted the danger of trying to understand steam from a book.

TE is a theoretical calculation, which indicates how much the loco should be able to move from rest.

It has no bearing on how fast said loco will be able to move said load, or for how great a distance. It's only use is as an indication as to if a loco will be able to restart a given load on a gradient, but extra maths is required, to allow for incline & curvature.

When you get involved with steam locos practically, you rapidly realise that the defining feature is the thing's ability to make steam, ie that which it converts to power. There's plenty of small shunting locos out there, with phenominal tractive efforts. What they can't do is sustain that for any distance. They literally "run out of puff". They are just intended to move a heavy load for a couple of hundred yards, then to spend the next ten minutes refilling the boiler. The key is heating surface, grate area, boiler pressure & degree of superheat. (this is where your model locos don't offer a realistic comparison).

With the smaller locos, the art is to work them to what the boiler is capable of generating. There is no point in thrashing the hell out of it, as you'll just have to stop. You work out what it will keep up with, and plod along at that. That is how the likes of the NYMR drag 7 - 8 Mk1's with a 56xx tank.

The chap that started this thread has asked some intelligent questions - I'd encourage you to actually get stuck in first hand. Steam is something that you can only truly understand by "doing".

 

[Ploughman]

Standard Length Unit

Also equates to 21ft.
At the time the standard overall length of a rail wagon.

 

[scotsman]

I've known up to 7 coach trains to run on the Strathspey (not including the Royal Scotsman), but in normal service we run 6 cars because Broomhill can only take 5 and the first door of the 6th coach - so the Guards are permitted to lock out the front 2 doors on the right hand side of the train.

 

[mumrar]

At the Severn Valley steam gala on 26th one opf the late runs (about 8pm off Kiddy) should be pannier tank 5764, Ivatt 2MT 46443 and a load of 10 coaches! That should be quite shouty away from Sterns restriction to say the least.

 

[scotsman]

Wow! That's going to be one hell of a train! Wish I lived closer so I could bash it/phot it.

 

[AndyJB]

At the Severn Valley steam gala on 26th one opf the late runs (about 8pm off Kiddy) should be pannier tank 5764, Ivatt 2MT 46443 and a load of 10 coaches! That should be quite shouty away from Sterns restriction to say the least.

Will have to make sure am behind that one!

 

[12CSVT]

The East Lancs got into a rather sticky situation a few years ago at one of their diesel galas (I think it was July 2003). They ran a 11 coach train top & tailed by 3 class 20s and a 37. On the way back to Bury the train stopped in the platform at Ramsbottom fouling the level crossing; at the same time an ambulance was approaching, blue lights flashing. I can remember the crews of the 20s frantically sounding their horns in an attempt to alert the driver of the 37 as to what was happening.

 

[Ploughman]

There was once a 20 plus coach working with 1 engine on the NYMR. (Photo in Moorsline)
It was an ECS working so may not count.