Imaginary Locomotives

[Suzie]

7 minutes ago, Mark Saunders said:

Sorry but Taurus Excretum is the main byproduct!

 

Sounds like scope for a digester in the next compartment  to make a bit of methane, mix that with the hydrogen, and we are running on town gas...

[rodent279]

1 hour ago, DenysW said:

According to the forest research website, wood pellets dried to 10% moisture have 45% of the calorific value of coal on a volume basis, meaning a wood-pellets-driven steam engine would need 2.2 times the bunker volume of a coal-fired loco.

What's the energy requirements of the drying & compacting process? Also you'd have to keep the pellets in a dry place, presumably humidity controlled to stop them absorbing moisture from the atmosphere.

[KeithHC]

Move to Iceland and operate all locomotives as fire less using geothermal steam.

 

Keith

[laurenceb]

Don't know what happened to it, but there was a proposal to fit a sterling engine into a Routemaster bus

[DenysW]

I've not even tried to take an integrated carbon-footprint look at the alternatives to coal, just thought that, if regulations forced the heritage sector to move away from coal, this is an opportunity for arm-chair designers (us) to propose a bespoke solution that might be better.

 

 So I agree with PenrithBeacon that late-design 2-6-4T's are a good conventional solution, unless the 19 ton axle-weight is just OTT, when which case the LMS 4F 0-6-0s have similar power but slightly lower axle loading.

 

But this isn't blue-skies, nor is it trying to make improvements over the cutting edge of the 1950s in steam traction for slow branchlines.

 

Suggestions?

[PhilJ W]

I was being quite serious when I suggested hot air as a substitute for steam. It has several advantages which outweigh the disadvantages of which there are some but not insurmountable. A few years ago there was someone who regularly attended the Southend model railway exhibition demonstrating has home made working hot air engines. One in particular I recall used the heat generated by a 3 volt torch bulb to work a small piston engine. Concealed within the boiler there could be a pressurised air tank* supplying air to the cylinders and instead of exhausting there could be a closed system incorporating a heater and a compressor returning the air to the tank. The air tank and pipework would have to be well insulated for efficiency. The power supply for the compressor and heater could be provided by batteries in the tender. To conserve energy the entire train could be fitted with regenerative brakes. *The air in the tank would be pre-heated and compressed. 

[DenysW]

The battery technology seems to exist, although a quick traul in the internet was not helpful on size or weight. A 4F locomotive is rated at 500 kW (700 hp), so a 10-hour day is nominally (up to) 5 MW-hr. A 7 MW-hr Tesla-brand battery has been installed in Japan to get one of their big trains to the next station in the event of a grid outage. It can be done. Recharging over 6 days (it's a heritage line) would take a 35 kW connection, bigger than a domestic car-charging circuit, but not outrageously bigger.

 

But why then an elaborate air-circuit? Just use a battery-powered electric motive unit?

[DK123GWR]

1 hour ago, DenysW said:

The battery technology seems to exist, although a quick traul in the internet was not helpful on size or weight. A 4F locomotive is rated at 500 kW (700 hp), so a 10-hour day is nominally (up to) 5 MW-hr. A 7 MW-hr Tesla-brand battery has been installed in Japan to get one of their big trains to the next station in the event of a grid outage. It can be done. Recharging over 6 days (it's a heritage line) would take a 35 kW connection, bigger than a domestic car-charging circuit, but not outrageously bigger.

 

But why then an elaborate air-circuit? Just use a battery-powered electric motive unit?

Because it isn't quite the same without the 'chuff-chuff-chuff-chuff'? Using electricity to drive may be more efficient, but using it to boil water retains the character of the locomotive more effectively as far as I'm concerned.

[Gibbo675]

1 hour ago, DenysW said:

The battery technology seems to exist, although a quick traul in the internet was not helpful on size or weight. A 4F locomotive is rated at 500 kW (700 hp), so a 10-hour day is nominally (up to) 5 MW-hr. A 7 MW-hr Tesla-brand battery has been installed in Japan to get one of their big trains to the next station in the event of a grid outage. It can be done. Recharging over 6 days (it's a heritage line) would take a 35 kW connection, bigger than a domestic car-charging circuit, but not outrageously bigger.

 

But why then an elaborate air-circuit? Just use a battery-powered electric motive unit?

Hi Denys,

 

It really is refreshing to read a post that has been written by someone that has read a physics book rather than the greenwash that is printed in newspapers and broadcast by the television stations.

 

Gibbo.

[Northmoor]

2 hours ago, DK123GWR said:

Because it isn't quite the same without the 'chuff-chuff-chuff-chuff'? Using electricity to drive may be more efficient, but using it to boil water retains the character of the locomotive more effectively as far as I'm concerned.

Not only is there no chuff-chuff but there's also no coal-burning and hot oil smell, a bit of steam but no smoke and it'll be clinically clean.  Which is not what the visiting public wants to experience.  You might as well just run a battery-powered coach, but unless the railway's location is everything (e.g. Snowdon Mountain Railway) almost no-one will turn up to ride on it.

[DenysW]

I am emotionally attached to the chuff-chuff-chuff. But I'm also attracted to the efficiency opportunities that steam turbines provide if you combine them with articulated designs.

 

I accept that for standard designs there isn't much in the way of benefit: Turbomotive was probably the same efficiency as her sisters given a statistical analysis, not the 6% better claimed. So less hammer on the track against a drive train that was worn out in only 10-12 years. But: an articulated 0-4-4-0 (in this duty) that follows Turbomotive's lead and retains enough energy in the steam to operate the boiler draft just from the front drive, and condenses the steam from the rear drive to recover the latent heat of vaporisation might give a big efficiency gain. It takes a lot of heat to convert water from a liquid to a gas/vapour, and throwing away all that heat just to shift air through a bed of coal seems a waste.

 

In a previous life I also used big centrifugal blowers where the angle of the vanes was adjustable to vary the output. I wonder (I'm not an engineer) whether this could now be applied to locomotive turbines to make them more flexible in output. Turbines seem more likely to have made design advances since 1940 than reciprocating steam mechanisms.

[Zomboid]

10 hours ago, PhilJ W said:

Has anyone considered hot air instead of steam? After all hot air engines have been around for years and work on similar principles to a steam engine. There will be no need to carry around water and the tender space could be used for batteries.

Here is a suggested source of hot air.

 

A Stirling Engine can actually run on hot air.

[MikeOxon]

CCGT

4 hours ago, Gibbo675 said:

Hi Denys,

 

It really is refreshing to read a post that has been written by someone that has read a physics book rather than the greenwash that is printed in newspapers and broadcast by the television stations.

 

Gibbo.

I agree - there's an awful lot of 'greenwash' about!  For example, here's a screenshot of current National Grid status, taken this evening from http://www.gridwatch.templar.co.uk/

 

 

Note contributions to demand are: Gas (CCGT) 53%, Nuclear 13%, Wind 4%, Solar 0% (it's night-time).  We also buy 10% from France (Nuclear).  The only time the figures hit the headlines is on the odd occasions when Wind exceeds Nuclear!

 

Infrastructure, such as railways, need reliable sources of power that simply aren't yet forthcoming from 'green' sources, unless you (justifiably) include Nuclear as 'green' (no CO2 emissions)

[Gibbo675]

1 hour ago, MikeOxon said:

CCGT

I agree - there's an awful lot of 'greenwash' about!  For example, here's a screenshot of current National Grid status, taken this evening from http://www.gridwatch.templar.co.uk/

 

 

Note contributions to demand are: Gas (CCGT) 53%, Nuclear 13%, Wind 4%, Solar 0% (it's night-time).  We also buy 10% from France (Nuclear).  The only time the figures hit the headlines is on the odd occasions when Wind exceeds Nuclear!

 

Infrastructure, such as railways, need reliable sources of power that simply aren't yet forthcoming from 'green' sources, unless you (justifiably) include Nuclear as 'green' (no CO2 emissions)

Hi Mike,

 

You are quite well observed with the above and you are indeed correct about stable supplies generally and also for railway traction. My main point about greenwash is that the only truth I've ever seen in a newspaper was fish and chips !

 

Gibbo.

[rockershovel]

All of these alternatives have been around a long time. They haven't, and won't succeed because they all suffer from various forms of the Law of Diminishing Returns, in its special applications relating to complexity and lack of flexibility. Steam Turbines work very well in large, primarily constant-speed applications - the bigger the better. Hot air engines have minor, very specialised applications but mostly, hydraulic or electric transmissions from conventional engines occupy those roles. Hydrogen propulsion requires elaborate systems to handle the fuel.  Electric traction works well but requires a large,  inflexible infrastructure. Nuclear power works very well but requires great care on use and in disposal of the end product. Fossil hydrocarbons became the dominant form of portable energy generation because of the nature of the fuel. 

[BernardTPM]

Has anyone worked out which causes less pollution? Producing hydrogen or making batteries? Both are nominally 'clean' when in use but both require considerable resources and raw materials to create and would need supporting distribution infrastructure. Batteries would also require safe disposal/recycling at life end.

[AlfaZagato]

...the nuclear option gives me a thought.

 

I have seen discussion recently of Thorium salt reactors.    They are safer & cleaner still than the more traditional Uranium solid-core reactors.   Uranium is still in use due to its potential weaponization.   Thorium's yield is lesser such that it makes poor bombs.   A thorium reaction still produces not inconsiderate energy, plenty enough to run power grids.   Sufficient lobbying & education may make replacing the power grid with Thorium salt power the truest green option.

 

In relation to this thread, though.   I wonder if a large-boilered steam loco could be turned nuclear?   A small Thorium salt reactor inside the firebox, duly lined with lead, using the excess heat to boil water for direct-action steam?   Skip the oft-tried and always-failed turbine step.

[Corbs]

Reminds me of Fireflash, the nuclear powered airliner from Thunderbirds.

[PhilJ W]

Another advantage of thorium is that it can be switched off like a light in case of an emergency. If Fukushima had been a thorium powered station it could easily have been shut down before the tsunami hit.

Edited August 11, 2021 by PhilJ W
fat finger syndrome

[ian@stenochs]

On 10/08/2021 at 14:53, laurenceb said:

Don't know what happened to it, but there was a proposal to fit a sterling engine into a Routemaster bus

 

Sorry to pedantic but I think you are referring to a STIRLING engine invented  by the Rev Robert Stirling in 1816.  There is a railway connection as he was father of Patrick and James who were both eminent locomotive engineers.

 

[MikeOxon]

I don't know what you guys have been reading about thorium but Thorium is not fissile and cannot itself be used as a reactor fuel. 

 

Thorium can be converted to an isotope of uranium (uranium-233) in a breeder reactor and the U-233 made in this way this could theoretically be used as a nuclear fuel for a conventional reactor.  This is analogous to breeding plutonium from U-238 (the most common uranium isotope) in a fast-breeder reactor.  The technology is far from simple and has never been achieved with thorium.  As far as 'green' issues are concerned it's a red herring.

 

Small reactors have been built but are only suitable for use as neutron sources.  The power output is usually only a few hundred watts and would not power a locomotive.

[The Johnster]

3 hours ago, AlfaZagato said:

Uranium is still in use due to its potential weaponization.

 

The very reason it should not be used and never should have been.  It is time the government came clean about the intent behind building nuclear power stations in the 50s and 60s; my brother-in-law was employed designing and intalling switchgear for them and was something of an enthusiast, claiming that the electricity would be so cheap it would not be worth printing the bills.  Yeah, right; I was 10 in 1962 and I didn't believe it then...

 

3 hours ago, AlfaZagato said:

Skip the oft-tried and always-failed turbine step.

 

With the exception of the Swedish 2-8-0s, which were very good by all accounts.

 

3 hours ago, Corbs said:

Reminds me of Fireflash, the nuclear powered airliner from Thunderbirds.

 

Not the best thought out name for a civilian airliner, and akin to the Royal Navy's tempting of fate with it's battlecruisers at Jutland or claiming that the Titanic could not be sunk, even by god (god, circa 1911, 'oh, really, you think so, do you?; lump of ice separates from glacier somewhere on the west coast of Greenland and starts moving south...).  That said, if I could model road surfaces like the Anderson's, I'd call myself a proper modeller!

[Gibbo675]

8 minutes ago, The Johnster said:

 

The very reason it should not be used and never should have been.  It is time the government came clean about the intent behind building nuclear power stations in the 50s and 60s; my brother-in-law was employed designing and intalling switchgear for them and was something of an enthusiast, claiming that the electricity would be so cheap it would not be worth printing the bills.  Yeah, right; I was 10 in 1962 and I didn't believe it then...

 

 

With the exception of the Swedish 2-8-0s, which were very good by all accounts.

 

 

Not the best thought out name for a civilian airliner, and akin to the Royal Navy's tempting of fate with it's battlecruisers at Jutland or claiming that the Titanic could not be sunk, even by god (god, circa 1911, 'oh, really, you think so, do you?; lump of ice separates from glacier somewhere on the west coast of Greenland and starts moving south...).  That said, if I could model road surfaces like the Anderson's, I'd call myself a proper modeller!

Hi Johnster,

 

I see that you have putting the Seven Liberal Arts to good effect there.

 

Gibbo.

[The Johnster]

Not guilty, Gibster; one needs to have been a scholar, ejermacaturised to degree if not doctorate level in a university, to practice such arts.  I am not a gentleman, either, that is, a person not of the nobility or aristocracy who is not a villein or peasant and owns property.  Nor am I a tradesman or merchant, nor a cleric.  In fact it would be difficult to place my rank in a feudal society, knave possibly, and they'd have prolly burned me at the stake as a heretic, especailly if they'd found out I was an atheist and hence a heretic..

[Gibbo675]

Just now, The Johnster said:

Not guilty, Gibster; one needs to have been a scholar, ejermacaturised to degree if not doctorate level in a university, to practice such arts.  I am not a gentleman, either, that is, a person not of the nobility or aristocracy who is not a villein or peasant and owns property.  Nor am I a tradesman or merchant, nor a cleric.  In fact it would be difficult to place my rank in a feudal society, knave possibly, and they'd have prolly burned me at the stake as a heretic, especailly if they'd found out I was an atheist and hence a heretic..

Hi Johnster,

 

You somehow missed out, WELSH !!!

 

Gibbo.