Imaginary Locomotives

[Northmoor]

11 hours ago, rodent279 said:

Wasn't there an Australian version of this? Think it was a 2000hp EE engine, with a 1-Do-1 or 2-Do-2 wheel arrangement.

Yes:

 

[melmerby]

30 minutes ago, AlfaZagato said:

All of you needing these silly locomotives for such short trains.   Let me tell you here stateside...

Is that the States in Oz where the heaviest trains in the world run?

 

 

[AlfaZagato]

5 hours ago, melmerby said:

Is that the States in Oz where the heaviest trains in the world run?

 

 

Nah, the USA, where everything is BIGGER and BETTER.

 

 

Get me out of here.

 

So, question for everyone here, what are the limits on width & height on the UK system?

[RLBH]

1 hour ago, AlfaZagato said:

So, question for everyone here, what are the limits on width & height on the UK system?

For freight stock, W6 loading gauge is 9' 3" wide by 13 feet high, but with a curved roof profile that limits height at the side. Bogie passenger coaches are limited to about 9' wide.

[Satan's Goldfish]

2 hours ago, AlfaZagato said:

Nah, the USA, where everything is BIGGER and BETTER.

 

 

Get me out of here.

 

So, question for everyone here, what are the limits on width & height on the UK system?

 

 

Ta-daa!

 

 

 

There is one somewhere that shows all the different UK gauges from W6 to W12. The larger gauges help with transporting larger shipping containers on conventional flat wagons rather than needing special low-level vehicles for them to fit in W6. Lots of useful stuff here including the British sizes: https://en.wikipedia.org/wiki/Loading_gauge 

 

I was always under the impressing that the Channel Tunnel was the largest loading gauge globally, looking at that link it definitely wins on width but misses out slightly on height to the US double stacks, but the Betuweroute looks to have (unsuccessfully) tried to combine both. Longest and heaviest are Australia mining operations... I'm not going to worry about checking if the fastest is in America or not... ;)

[Satan's Goldfish]

9 hours ago, rodent279 said:

If you assume boiler efficiency at 65%, then with a loco developing say 2000 kw indicated power, at say 50% efficiency for a turbine, you are going to need a 4000kw boiler. At 65% efficiency that's 6153kw, or around 8000hp, required from the elements.

Not sure what sort of efficiency you could expect from a well designed steam turbine, but I think 50% would be on the high side.

 

Interesting numbers... Exploring it a step further then, we are looking at changing to an electric boiler for our central heating and hot water later this year. One of the points they like to mention with electric boilers is that because there's no flue there's almost no waste heat disappearing to the outside world. This is obviously at much lower temperatures and pressures than a conventional steam locomotive would be.

 

But what if rather than heating water to the levels required to drive pistons or a turbine, it stays in a sealed system at lower pressures and temperatures and is used to drive stirling engines https://en.wikipedia.org/wiki/Stirling_engine which are also more efficient. (If they'd received as much attention as steam and diesel have over the years I'm sure their power to weight ratio could theoretically be quite competitive) 

 

Ignoring the obvious much simpler solution of using overhead electrical power to drive a motor connected to the wheels, the locomotive in this case would be:

Pan collecting electricity from overhead wires

Heating element in a closed circuit low pressure system (heating coil directly on 'hot' side of the engine even removing water entirely from the system?)

Stirling engine with 'cool' side exposed to ambient air temperature

Mechanical drive to wheels.

 

Don't think it would be possible to convert an existing steam design to it though.

[rodent279]

It's just a guess, but I think that conventional electric transmission would still win out on efficiency and weight, but it's still an interesting idea when you begin to think about it.

The boiler I'd imagine would be some development of a water tube or flash boiler, rather than simply a loco boiler with no firebox and elements instead of tubes.

I wonder if it could be done in model form?

[RLBH]

15 minutes ago, rodent279 said:

 

I wonder if it could be done in model form?

There was a Hornby 00 gauge live steam A4 a while back; whilst it was 00 gauge, it needed special track and a special power supply to handle the current to power it, and was very expensive - about £1,000 in today's money, I believe, not allowing for real-terms price increases for models. On top of that, if (when) the thing derailed, you had a boiler that was, well, boiling, and moving parts to contend with.

[DavidB-AU]

22 hours ago, rodent279 said:

Wasn't there an Australian version of this? Think it was a 2000hp EE engine, with a 1-Do-1 or 2-Do-2 wheel arrangement.

 

The 2-Do-2 was the WAGR X class which had a 1045hp Crossley engine.

 

Cheers

David

[34theletterbetweenB&D]

12 hours ago, rodent279 said:

...the efficiency of the boiler would probably be a whole load higher, as you wouldn't be throwing heat out of the chimney instead of using it to heat water. Likewise, you wouldn't need to have to exhaust steam to atmosphere to get a draught, with all the attendant problems of back pressure. Plus you could use a condenser and re-use the water...

But why water as the working fluid?  Historically used for steam engines because it was cheap and available, and had done its stuff in sufficient kettles for the penny to drop. But it is encumbered with very high latent heat to reach the useful gaseous state, not so good.

 

But now we can surely formulate an alternative compound for use in a closed circuit system, ideally with intrinsic lubricating properties for the mechanism, and spontaneous ignition on contact with oxygen for a 'self alerting' capability if the safety valves open for an over pressure incident. Not my field at all, some other clever chap or chapess needs to chip in at this point: but once encountered a chap who had worked for some years with boranes, and that sounds like fun stuff...

[rockershovel]

Why water? Well, it’s abundantly available, as cheap as it gets in bulk, has a national distribution infrastructure in most countries... its non-flammable, non-toxic, can be vented to atmosphere or poured into the drains; in fact it’s pretty much the definitive medium for such a use. 

 

 

[Corbs]

I'd love to do some US/Auzzie imaginary locos, but the thing is, Hornby do those oh-so-useful pictures of the perfect side-on view of the loco...

[rodent279]

23 minutes ago, 34theletterbetweenB&D said:

But why water as the working fluid?  Historically used for steam engines because it was cheap and available, and had done its stuff in sufficient kettles for the penny to drop. But it is encumbered with very high latent heat to reach the useful gaseous state, not so good.

 

But now we can surely formulate an alternative compound for use in a closed circuit system, ideally with intrinsic lubricating properties for the mechanism, and spontaneous ignition on contact with oxygen for a 'self alerting' capability if the safety valves open for an over pressure incident. Not my field at all, some other clever chap or chapess needs to chip in at this point: but once encountered a chap who had worked for some years with boranes, and that sounds like fun stuff...

Why not indeed, and there are probably many advantages to using a liquid other than water, but @Rockershovel makes some very valid observations. Not my subject area either by any means. 

[rockershovel]

8 minutes ago, rodent279 said:

Why not indeed, and there are probably many advantages to using a liquid other than water, but @Rockershovel makes some very valid observations. Not my subject area either by any means. 

 

I’m not convinced that “encumbered with a high latent heat” is quite the right term. I stand to be corrected on this, but as I understand it, the energy transmitted to the water in vapourising it (and subsequently, the energy transmitted to the steam in superheating it, if so, and to the feed water as heat) is the energy which appears as work at the pistons? 

 

The efficiency losses are the heat which is radiated by the boiler, or expelled up the chimney as hot exhaust, plus friction losses in the mechanical parts and air resistance - no? 

 

Edited February 27, 2019 by rockershovel

[rockershovel]

Regarding the general subject of articulated steam locos on U.K. lines, bear in mind that the unique British design of mostly twin or multiple tracks, elevated platforms and all sorts of lineside furniture means severely restricted clearances for cylinders and running gear plus severe restrictions on side-throw of Mallet types in particular. 

 

American style patterns of huge, low-speed drag freight never developed.

 

The LNER showed that it was quite possible to build an entirely conventional 2-8-2 which could haul trains which couldn’t be accommodated on the network. BR did this with the 9F, although they made better use of the resulting loco. 

[Coryton]

1 hour ago, rockershovel said:

Why water? Well, it’s abundantly available, as cheap as it gets in bulk, has a national distribution infrastructure in most countries... its non-flammable, non-toxic, can be vented to atmosphere or poured into the drains; in fact it’s pretty much the definitive medium for such a use. 

 

 

 

For an open system like a steam engine, definitely.

 

If you're talking a working fluid for a closed system I don't see that those criteria are so important.

 

We're happy to use fuel that fails to meet much of that.

[34theletterbetweenB&D]

42 minutes ago, rockershovel said:

 

I’m not convinced that “encumbered with a high latent heat” is quite the right term. I stand to be corrected on this, but as I understand it, the energy transmitted to the water in vapourising it (and subsequently, the energy transmitted to the steam in superheating it, if so, and to the feed water as heat) is the energy which appears as work at the pistons? 

 

The efficiency losses are the heat which is radiated by the boiler, or expelled up the chimney as hot exhaust, plus friction losses in the mechanical parts and air resistance - no? 

 

All the energy input required to heat the water from cold to boiling point and then to evaporate it as a gas - steam - is completely lost in the exhaust of a non-condensing steam engine. Once the engine and smokebox is warmed through the water leaves the pistons as steam - still in the gaseous state - and the water typically only reverts to vapour after it is exhausted to atmosphere. If the fire is achieving near complete combustion a small translucent zone can be observed above the chimney top, so there the exhaust is all gaseous, the condensation of the water content back to vapour occurring immediately above as the billowing white clouds. (A large condenser system - see power station cooling towers as an example - is required to obtain any useful output from this energy input. )

[DavidB-AU]

2 hours ago, Corbs said:

I'd love to do some US/Auzzie imaginary locos, but the thing is, Hornby do those oh-so-useful pictures of the perfect side-on view of the loco...

 

Some plausible options would be what if New South Wales, Victoria, South Australia and the Commonwealth Railways had largely stuck with British manufacturers after 1951 instead of finding ways around the currency restrictions to buy GM and Alco. 

 

Cheers

David

[RLBH]

Some BR Standard musings, of mostly-sane nature. Much of this plays into a scenario where nationalisation is a foregone conclusion from mid-WW2, allowing Riddles to lay groundwork in the war years and have BR build Standards from the outset instead of Big Four designs.

• A 6' 8" version of Duke of Gloucester, which would take the place of Peppercorn A1s, Merchant Navies, and the last Coronation.
• A 2-8-2 based on the big Class 8P with 6' 2" drivers. The 2-8-2 is the BR Standard version of an LNER P2 - might it be useful on Shap and Beattock, or would the lack of a 4-wheel bogie forward be too restrictive?
• The originally-planned 6' 8" driver express passenger Class 7 Pacific, to partner a 6' 2" mixed traffic Pacific. Ultimately, good front-end design meant that 6' 2" drivers could achieve the required speeds, so we got the mixed-traffic Britannia and Clan classes instead.

• A BR Standard version of a Gresley V2. Shortened Britannia boiler, Clan cylinders, and 5' 8" drivers. Works out as an  8P7F, oddly, but doesn't actually seem to be very useful. Probably not worth bothering with - it doesn't really offer anything that you can't get from a Britannia at lower axle load. If making a wide-firebox goods locomotive out of this boiler - or indeed the Clan boiler - the 2-8-2 seems to be the better bet. It seems like Edward Thompson might have been on to something with the A2/1, and Riddles with putting 6' 2" drivers on the Pacifics.

• A BR Standard version of a Thompson K1. Shorten a 5MT boiler, keep the cylinders, stick 5' 3" drivers off a 4MT 2-6-0 on it. Axle load is just under 20 tons, 30,685 pounds tractive effort, and 5P6F power classification. It would, of course, perform the same duties as the K1. Probably the most sensible member of this group.
• A Class 5 2-6-2, comparable to the LNER V4. Class 5 4-6-0 cylinders, 5' 8" drivers, and an all-new boiler. The new boiler would make it impractical, but it's a nice thought.
• A Class 4P 4-4-0, using the boiler and cylinders from a Class 4 4-6-0 and 6' 2" drivers. Not quite sure what it would be good for, apart from as a like-for-like replacement for LMS Compound 4-4-0s and LNER D49s, but it seems like a logical member of the family.

[The Johnster]

17 hours ago, melmerby said:

Is that the States in Oz where the heaviest trains in the world run?

 

 

I have an idea it might be Mauretania, where they run very long and heavy iron ore trains.

[melmerby]

43 minutes ago, The Johnster said:

I have an idea it might be Mauretania, where they run very long and heavy iron ore trains.

The heaviest ever run was in Australia where BHP Billiton ran a train of nigh on 100000 tons with 8 AC6000s distributed down the train.

They normally run half this amount

[Northmoor]

5 hours ago, RLBH said:

Some BR Standard musings, of mostly-sane nature. Much of this plays into a scenario where nationalisation is a foregone conclusion from mid-WW2, allowing Riddles to lay groundwork in the war years and have BR build Standards from the outset instead of Big Four designs.

Some interesting designs, but still running into the same issue as reality.  The steam locos were still being built while the specifications for their replacements were being passed to manufacturers and the traffics that both the steam locos and their replacements were built for, were being withdrawn as unsuited to continued rail operation.

 

But hey, this your model railway and Rule One applies!

[RLBH]

14 minutes ago, Northmoor said:

Some interesting designs, but still running into the same issue as reality.  The steam locos were still being built while the specifications for their replacements were being passed to manufacturers and the traffics that both the steam locos and their replacements were built for, were being withdrawn as unsuited to continued rail operation.

 

But hey, this your model railway and Rule One applies!

A few of them are actually intentionally bad ideas, but the kind of bad idea that could well have seemed to make sense. In that respect, they're very much like the entire programme of 'modern' steam traction.

[rockershovel]

8 hours ago, 34theletterbetweenB&D said:

All the energy input required to heat the water from cold to boiling point and then to evaporate it as a gas - steam - is completely lost in the exhaust of a non-condensing steam engine. Once the engine and smokebox is warmed through the water leaves the pistons as steam - still in the gaseous state - and the water typically only reverts to vapour after it is exhausted to atmosphere. If the fire is achieving near complete combustion a small translucent zone can be observed above the chimney top, so there the exhaust is all gaseous, the condensation of the water content back to vapour occurring immediately above as the billowing white clouds. (A large condenser system - see power station cooling towers as an example - is required to obtain any useful output from this energy input. )

 

Given that the thermal efficiency of a steam locomotive seems to have been 5-6%, I don’t doubt that there was waste heat pouring out everywhere.. I’ve heard Harley Davidsons described as “devices for converting fuel into heat and noise, without actually producing power” but steam locomotives put them to shame... but arent they something special while they are doing it? 

 

Edited February 27, 2019 by rockershovel

[Clive Mortimore]

8 hours ago, 34theletterbetweenB&D said:

All the energy input required to heat the water from cold to boiling point and then to evaporate it as a gas - steam - is completely lost in the exhaust of a non-condensing steam engine. Once the engine and smokebox is warmed through the water leaves the pistons as steam - still in the gaseous state - and the water typically only reverts to vapour after it is exhausted to atmosphere. If the fire is achieving near complete combustion a small translucent zone can be observed above the chimney top, so there the exhaust is all gaseous, the condensation of the water content back to vapour occurring immediately above as the billowing white clouds. (A large condenser system - see power station cooling towers as an example - is required to obtain any useful output from this energy input. )

It is the need to condense the steam after it has gone through the turbines that makes a power station very inefficient, about 35%. The steam leaving the low powered end of the turbine is almost a vacuum. It needs to be pumped back into the boiler, the water/steam in the boiler and turbine cycle is as pure as can be possible and is in a closed circuit. The only way it can be pumped back is by converting back to water. The condenser has pipes through it where river or sea water is pumped and this reduces the temperature of the steam and it returns to its liquid state. The heat exchange makes the river/sea water very hot. The hot river water coming out of the condensers is far too hot to pump straight back into the river so needs to be cooled. To do so is to pump it up high and let it rain down using the air to cool it. The inside of a cooling tower is like a circular waterfall.  Even after going through the condenser the water is still warmer than the river and normally encourages river plant and fish to grow well. Power stations by the sea pump the warm water straight out, quite some way below the low water mark as there is enough volume of sea water to dissipate the heat therefore not requiring cooling towers.  

 

Basically the steam seen (normally on the news when discussing pollution) coming out the top of a cooling tower is steam from river water not the boilers.

 

An electrically heated steam loco would still need to exhaust its steam to draw the heat (hot air) through the boiler tubes to heat the water etc. just like one fired by wood or fossil fuels.