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Operating range of small tank locos


petrox
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Apologies if this topic has been covered before at some point.

What would be the typical operating range in mileage of a small tank engine, such as a GWR Pannier, or an SR M7 or O2, before taking on coal and/or water? 

I assume water would be needed before coal, and maybe the duty being performed would affect the range, whether on a local passenger or a pick-up goods.

I note that Plymouth-Tavistock (about 15 miles) trains were usually 14xx/auto operated, but Plymouth-Launceston were usually 45xx - was this because a 14xx would need a refuelling stop on the longer working?

The reason I ask is that my South Devon layout has a mythical branch from Dartmouth (St. Petrox on the model) to Plymouth, about 35 miles - do I need to allocate a 45xx or would a 14xx or 64xx be suitable?

 

Many thanks in advance to the many RM gurus who I trust will know the answer.

 

Pete

 

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I don't know the answer, though no doubt the weight of the trains will also have some bearing on the loco class allocated.

The Teign Valley route from Exeter to Newton Abbot (approx 20 miles) was worked by a mix of 14XX (on auto trains) and 45XX classes, while the Exe Valley Route from Exeter to Dulverton (approx 25 miles) was also worked by 14XX class and 64XX class on auto trains. 

 

cheers

Edited by Rivercider
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Coal would be filled before leaving the shed and would last all day. Look at the amount of coal they filled tenders with for example. Tank engines would be the same.

 

http://www.gwr.org.uk/no-tenders.html

 

 

Water was freely available. Many stations had a water crane or tower. Branch lines were pretty leisurely so probably had quiet spells in the schedules to fill up.

 

It did come up recently that a 14XX or 58XX worked regularly from Wrexham to Bala. That's quite a distance. Something like 30 to 40 miles by train in quite hilly countryside with a lot of gradients.

 

 

 

 

Jason

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Don't make the mistake of thinking that an M7 is a small loco; it is as big as many modest 4-4-0, and was conceived as both a main-line and suburban engine. They have a decent-sized bunker, and were used for a short period on London to Portsmouth trains, and for much longer on Reading and Windsor services. Their descent to branchlines really only became complete once the outer suburban electrifications on the SW were completed in the late-1930s.

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32 minutes ago, Nearholmer said:

Don't make the mistake of thinking that an M7 is a small loco; .... Their descent to branchlines really only became complete once the outer suburban electrifications on the SW were completed in the late-1930s.

... and the alternative of fitting a superheated boiler wasn't really a good idea !

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3 minutes ago, Nearholmer said:

Don't make the mistake of thinking that an M7 is a small loco; it is as big as many modest 4-4-0, and was conceived as both a main-line and suburban engine. They have a decent-sized bunker, and were used for a short period on London to Portsmouth trains, and for much longer on Reading and Windsor services. Their descent to branchlines really only became complete once the outer suburban electrifications on the SW were completed in the late-1930s.

 

Same size as a Small Prairie (clue is in the name) but with a lower tractive effort and much lower BR power rating.

 

2P as opposed to a 4MT. 

 

So yeah, tiny...

 

 

 

Jason

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On a journey from Tavistock South to Tavistock North (strange one I know) it was noted in the working timetable that water would be taken on at Devonport, Kings Road.

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From a slightly earlier era, on the LBSCR, Stroudley's tank locos D1 and E1 were averaging 20¾ lbs/mile and 22.4 lbs/mile respectively on passenger duties around 1882. The 0-6-0 E1's had a bunker capacity of 1¾ tons of coal, which would give a range of 175 miles, more than enough for a 50 mile trip from London to Brighton, and then return, not that that would be a regular duty. The Southern did trials comparing LBSCR, LSWR and SE&CR 4-4-0 locos, showing 40, 30 and 31½ lbs/train-mile, the LSWR figure showing the benefits of super-heating. In their prime, Stroudley's Gladstones averaged around 30 lbs/mile, and carrying 3½ tons of coal in their tender could run 250 miles between re-fuelling.

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1 hour ago, Steamport Southport said:

Same size as a Small Prairie (clue is in the name) but with a lower tractive effort and much lower BR power rating.

 

The driving wheels of an M7 are about a foot bigger, which is a large part of why the TE is lower, the rest being down to 25psi difference in boiler pressure. Its a fairly fast loco, designed to pull, by later standards, light trains. The better comparators are various 4-4-0, the GWR Bird class, might be one that has similar vital statistics, and dates from about the same time, I think.

 

How BR decided power classifications, I don't know, but the two locos were designed for different jobs.

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If we rework the question to "what locomotives would the GWR have used on my fictional branch" ,  then gradients are going to play a significant role, I suspect even more important than water capacity. I suppose in a dream world you might produce a gradient profile for your fictitious line and then compare with other GWR branches, but then you maybe need to design your route and civil engineering which all gets a bit out of control if you just want a credible model. And to complicate there were plenty of branches that were not run with auto trains, but used standard tank engines, and these might even be turned at each end. 

 

So I think I might look at it from a different direction. What is my planned coaching stock? If its going to be auto trailers then 45s can be ignored, it will be a 14 if there are one or two trailers and not too steep, or a 64 if up to four trailers and/or more gradients. Auto fitted 45s were a specific BR era usage in S Wales, you can ignore that option. 

 

If you don't want trailers then the choice is wider and includes 57s as well as 45s, and they might even be turned at the terminus. And if you consider your terminus has a small turntable you can even add 2251 or Dean Goods to the mix. 

 

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How would your proposed line be worked?

I would imagine services would be out and back from Plymouth, with the locos being fully coaled at Laira before each trip. At Dartmouth St Petrox the shed would have a wagon of loco coal or small coaling stage to enable bunkers to be topped up as required, particularly on the loco that is shedded there over night,

 

cheers

Edited by Rivercider
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Many thanks for the wise words of advice.

It seems that my fictional branch Dartmouth/St. Petrox - Plymouth can be worked comfortably by a 14xx/single auto combination, but I will allow time on the operating schedule for a water stop at Kingsbridge.

Incidentally (as I am sure many know) such a line through the South Hams was proposed at various times between 1860 and 1890, but never happened - in my world the line has survived into the 1950's, albeit with only light traffic and short trains (Rule 1 applies). If the line had been built, I guess the Brent - Kingsbridge branch might not have happened. 

Many thanks once again.

 

Pete

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Abercynon auto diagram 'JB', the (in)famous 'St Fagan's Pullman', daily work Abercynon-Pontypridd light engine, attach to 2 auto trailers, work to Cardiff Clarence Road via Tonteg, Ty'n y Caeau Jc, St.Fagan's (South Wales Main Line), and Cardiff General, about 22 miles.  Then perform 2 return trips Clarence Road-Penarth, 20 miles all in, then return to Pontypridd via St Fagan's etc, crew relief, and full repeat performance in afternoon, finishing up light engine Pontypridd-Abercynon.  I make that something like 128 miles in the day's work, on one load of coal, quited tightly timed with uphill work in both directions, with a 64xx.  The bunker and boiler on a 48xx is more or less the same as a 64xx, so a 48xx would be cabable of similar work with a smaller load. 

 

Many small tank loco passenger jobs were like this, two or more coverings of the ground in a single duty with one bunker full of coal, which was expected to last you all day until you got back to the shed.  Water is more easily available and there is usually plenty of time and opportunity to top the tanks up on work that involved a lot of stopping at stations and waiting to connect with main line trains.

 

Steam locomotives were kept in steam for periods of about 10 days at a time, 'light steam' overnight or when the loco is on shed, as a major cause of problems in steam locos is the repeated expansion and contraction if you let the loco go cold and have to raise steam from a cold state.  The fire may be dropped and then relit but hot steam under pressure is always in the boiler until, after about 10 days of work, the tubes have to be cleaned, and the loco is out of service for about 48 hours as the boiler must be drained down and the firebox cooled enough for the boilersmiths to work inside.  Bringing her back up to working heat must be done carefully and gently to avoid stress on joints, glands, and especially the firebox/boiler interface.

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The IWSR has to re-coal its Terriers and the 02 at lunchtime for a day's work.

 

in the 1920s when the 02s were transferred to the island AB McLeod found their bunkers weren't big enough for a day's work so had them enlarged. I believe at that time the loco and crew stayed together for the day's work.

 

On the K&ESR locos are often re-fuelled during a break whilst taking water at Rolvenden.

 

Water is taken as and when required.

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There were no doubt places where a water supply was available but would not be used if it could be avoided. For example chemically unsuitable water (very hard etc) or because the water supply was from the mains as opposed to a railway-owned source, and so would be metered and charged for.

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You can say that most tank engines would have been able to operate all day on a duty with at least 70 odd miles. Based on the lighter loadings of many GW branchlines this may have been higher. As others have said its water which is the key. As an old inspector said 'never go past a column without taking a drop' 

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There were surprising locations with little or no water; for example, Clarence Road, a commuter branch serving Cardiff Docks, had none, which must have been exceptional for a terminus.  Of course, Cardiff General was only a mile away...   Another one was the downhill run in the Rhondda Fawr valley, between Treherbert and Porth.  Because of the use of 'incline working'  locos had to pull loaded coal trains with their handbrakes pinned down even downhill, and needed to work fairly hard, and there was only one column avaialble to trains on the down line, at Ynyshir.  It was on a steep falling gradient and not the easiest of places to stop as accurately as you needed to for topping up the tanks, especially with heavy trains and despite the pinned down brakes.  900ton loose coupled coal trains do not always behave predictably and are capable of messing you about with momentum once they are moving, even slowly.

 

Pontypridd had water columns but was no good because stopping for water there with a long coal train blocked the junction, and if you missed Ynyshir the next chance was Maesmawr, well south of Ponty!

 

This was of course the realm of 56xx and the like, not of 'small tank engines', and while it is true enough by and large to assume that wherever there was a station there was water, especially for passenger trains, it shows that there was not always a guarantee of it.  Freezing weather or drought further complicated the issue, and loco crews were never really fully relaxed about water and kept their eyes on the tank gauges.  A hard working steam locomotive uses very large amounts of the stuff.

 

Another factor in South Wales was the prevalence of fairly large tank engines with small driving wheels.  The 56xx, 42xx, 5202s, that were the area's bread and butter had less 'range' than the large prairies or Taff As with larger driving wheels that would go further per turn of the wheels, resulting in a preference for such locos on the longer runs.  The 8-coupled tanks suffered badly from leaking tanks on the sharp curves of the Monmouthshire Valleys, which further reduced how far they could go without a fill, or how long they could last.  This was ultimately because of flexing in the frames as the wheels got to the limits of their sideplay, which strained the rivetted joints in the tanks.

 

At St.Deveraux. a station between Abergavenny and Hereford, the signalman kept trout in the water tank, which ended up in loco tanks occasionally.  Try explaining to the inspector that you had to drop the fire on the running line because the injector was blocked by a dead trout...  You could, apparently, buy these to take home for dinner, they were corn fed and very tasty!

 

H20.  It's not just water, you know!

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9 hours ago, The Johnster said:

 

 

At St.Deveraux. a station between Abergavenny and Hereford, the signalman kept trout in the water tank, which ended up in loco tanks occasionally.  Try explaining to the inspector that you had to drop the fire on the running line because the injector was blocked by a dead trout...  You could, apparently, buy these to take home for dinner, they were corn fed and very tasty!

 

H20.  It's not just water, you know!

that reminds me of a Thomas the Tank Engine episode, only a river was the source of the water!

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1 hour ago, The Lurker said:

that reminds me of a Thomas the Tank Engine episode, only a river was the source of the water!

I believe just about all of the tales in the original books had a foundation in real events. Sadly once the TV companies started on their own plots that was lost. 

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20 minutes ago, JimC said:

I believe just about all of the tales in the original books had a foundation in real events. Sadly once the TV companies started on their own plots that was lost. 

Did I read recently of a case where eels were deliberately kept in the loco tender to keep the water weed free?

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In the early days of the Bishops Castle Railway water was sometimes scarce in BC so an old tender was filled from the river at Horderley and conveyed to BC where minnows could be seen swimming around in it.  For a period the use of water in the town was restricted between 7pm and 7am which led to a visit to the Town Clerk from a driver who complained that 7am was too late to get up a head of steam for the first train out.  Upon the Town Clerk asking why he couldn't fill it up before 7pm the previous day he explained that it was useless as the tender leaked and would be empty by morning.

 

The Bishops Castle Railway 1865-1935 by Edward Griffith.

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