Current and Proposed New-Builds

Austerities were built as shunting locos, but not all 0-6-0Ts were. Generally, with a shunting loco you make then under-boilered (or over-cylindered, it amounts to the same thing) so they have plenty of tractive effort to shift big loads, but the cylinder power will be in excess of the boiler power, so they will run out of steam rapidly. That's no problem for a loco doing stop-start work, and in fact is advantageous, because the small boiler power helps avoid standby losses during inevitable periods when nothing is running.

Not all 0-6-0Ts were shunting engines though; plenty were made for passenger work with a more sustained duty, and they tend to be proportioned such that ideally the boiler can keep up with the demand from the cylinders for a sustained period.

The section in Holcroft about the design of the Maunsell Z class is worth reading for a discussion about the particular issues of designing a (heavy) shunting engine. In BR terms, it was a class 7F engine in terms of its ability to shift a load, but with a boiler from a class 2F 0-6-0.

Tom

 

This is basically what I was thinking of.
By "modernising" a locomotive that was originally designed for shunting, it could be more suitable for heritage railway work.

 

Austerities had their origins as shunting engines however their boiler capacity is such that it's suitable for many heritage railways to use and you can see that as they pop up on many railways (not some of the more challenging ones though). Their front end arrangement in the smoke box does need a tweek to improve their performance but apart from that will do the work required especially as they have larger wheels more useful for speeds up to 25mph unlike many other shunting locos. The only other downside is the slightly shorter wheelbase although I never thought that too much of a problem if kept below the permitted speed!


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There are some tweeks that can improve a locomotive but it gets to a point that it becomes impossible. Take the humble industrial tank loco yes you can improve it (see my post on Austerities) but with small wheels and poor balancing (i.e. balancing designed for much lower speeds) a rough ride is all you will get. So your left with a boiler that has sufficient capacity but downstairs in need of a radical rebuild which at that point you ether build a new loco or you use what bits you can on a "franklins tune" (nice one spell checker) locomotive! These days I can see little point in using what bits you can as manufacturing is such these days that we can make most things with the right amount of cash.


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Wouldnt have thought rebalancing an 0-6-0 constitutes a radical rebuild. Even increasing the wheel size wouldn't be a massive undertaking in terms of design/ engineering ( though a fair bit of money for not much in return...)

 

The austerities which lasted towards the 70s were mostly Porta altered ones or variations thereof. With klychap, gjisels and suchlike. So consideration was made on improving performance mostly in ncb ownership.

 

But that was mainly to allow to allow the use of lower grade fuels - in the case of the Giesl it was an attempt to burn slack coal without ejecting it up the chimney.
As industrial locos there was no need to improve "performance" in the way we are discussing here. The requirement was for a maximum effort at low speeds for a short period of time - something they were designed for and did very well.

 

Considering the quality of some of the coal heritage lines are asked to use these days might be worth considering again?

 

Not sure where you are getting your supply, but I’ve looked at plenty of photographs of coal on locomotive tenders from the 19th century onwards, and I’d say the stuff we get is much better than our forebears had, better graded and with less slack. The main issue is you don’t know what you are going to get from week to week, so every day can be a learning experience - but the overall quality is generally pretty good in my experience. YMMV.

Tom

 

Like Tom, I reckon the coal we presently get is as good as that used by BR in the 60's. I'ts generally washed and graded, which it wasn't then. I can't compare it with earlier times, though. I may be old, but not that old.

 

It would be interesting to see what sort of performance you could get out of the surviving Porta modified industrials if the Porta modifications were restored.

 

Well there's bits about.

I also believe Nigel Day of this parish went about putting lempor exhausts in Pecket locos to good result.

 

Just out of interest Tom, and bearing in mind DEFRA's recent declarations - is there an argument for an industry wide search for alternative fuels for our steam locomotives? E.G. Biomass pulverised fuels. The reason I say this, is that most pulverised biomass fuels are too coarse for the power industry which represents challenges for them (using coal dust by comparison which can be finer and therefore more easily controllable) - but where we are literally throwing in lumps of stuff to burn, could we adopt such fuels more easily because of the nature of the coal > firebox relationship steam locomotives have?

 

By volume, what is the average calorific value of biomass as compared to coal? Volume as opposed to mass, because if the calorific vaue is low compared to coal, then carrying sufficient fuel may be one problem. Another which springs to mind is how well the fire bed would survive the induced draught from the blast pipe, particularly on hard working locomotives. From memory, isn't biomass injected into power station furnaces in powder form? I suspect that for main line use, oil firing may well be the only option. Ditto lines like the NYMR which are steeply graded in parts.

 

I’m reminded here of the success of Bulleid’s peat burner...


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A fair comment. I'm not suggesting running a Bulleid Pacific on turf, by the way...! Here's CC1 for context.

Good question.

Here's a source for some interesting reading. It looks as if Biomass has some way to catch up to the main fossil fuels. Biomass versus fossil fuels

Answering my own question I guess...!!!

 

Indeed, theres an American ? Chap Wolfgang Fengler whose quite keen on the Biomass for steam done quite a bit of work on this and presented papers to the ASTT
https://csrail.org/who-we-are/
https://csrail.org/torrefied-biomass/
Wonder if its possible to fuze some pulverized coal into the stuff to improve substance and retain the nice smell....

 

Great set of links. Including this handy table helping to illustrate the issues asked about earlier RE calorific value.



Torrified Biomass...never heard of this. Now reading it up. Fascinating stuff.

 

In earlier times some countries, such as the USA, had a lot of wood-burning steam locos, which presumably performed perfectly well for the needs of those times. If you're designing a steam loco from scratch (this is a new-build thread!) you can provide a large enough grate area and a large enough tender to cope with biomass. But it would make sense to get the maximum useful power for the amount of fuel burnt by including at least some of the Chapelon/Porta/Wardale improvements. I suspect that steam injection into the firebed to prevent clinker formation wouldn't be needed with biomass fuel, but does anyone know?

 

Clinker tends to form when impurities in coal ( minerals, ash) melt at very high temps and then re solidifies and fuses as it cools - difficult to imagine Biomass reaching the same kind of temperatures or having the same ash/mineral content as coal so think you 're right.
The torrefied stuff looks superb on paper, the main worry of course is not delivering it to the firebox, the Americans want to do that mechnically anyway so its got to be good for that, its what happens to it once its part burnt through... i.e if it behaves like popcorn it will be shooting out of Lempors with half its energy unused...