Imaginary Locomotives

[Flying Pig]

3 hours ago, jjb1970 said:

One of the more impressive narrow gauge designs for working steep bits was the JNR EF-63, they were Bo-Bo-Bo electrics of 2.55MW operated in pairs for banking trains over the Usui pass which had 1 in 15 gradients.

 

The RhB Allegra units are rated at 2.6MW on 11kV AC and will climb similar gradients between Chur and Arosa with three additional carriages and a couple of loaded ballast hoppers in tow, though they are considerably more modern than the Japanese trains.  It does look a little bizarre to see what appears to be a tram hauling such loads.

 

Switzerland is perhaps a bad example because they institutionally love trains and many lines thrive that would have been long closed in the UK.  I don't know how you get networks of electric trains with tail loads in the UK but it's an appealing idea.

[DenysW]

No votes for Snow Hill sharing its capacity with trams? Or the 1:10 coped with on the Sheffield system?

 

Apparently Manchester doesn't have trams, just Metrolinks.

Edited August 29, 2022 by DenysW

[SteamedLyons]

Crosti 7MT anyone? Perhaps should've added some Caparotti gear? 😉

 

[Michael Hodgson]

The way the economy is going, I'm going to have to start putting imaginary locos on my wishlist !

[The Johnster]

That’s nothing; I’m going to have to have an imaginary wishlist cos I can’t afford a real one…

[Ramblin Rich]

When I was a child, I had imaginary friends.

Now I'm grown up* I have an imaginary layout....

 

 

*allegedly 😉

[Flying Pig]

2 hours ago, Ramblin Rich said:

When I was a child, I had imaginary friends.

Now I'm grown up* I have an imaginary layout....

 

 

*allegedly 😉

 

Only one?  I think you might have missed the point of imaginary layouts.

[PayntersDocks]

10 hours ago, Ramblin Rich said:

When I was a child, I had imaginary friends.

Now I'm grown up* I have an imaginary layout....

 

 

*allegedly 😉

Now there's an idea for a thread! 1 mile long London Victoria To Brighton Mainline in about 1950 anyone?

[PhilJ W]

37 minutes ago, PayntersDocks said:

Now there's an idea for a thread! 1 mile long London Victoria To Brighton Mainline in about 1950 anyone?

Quite possible if its a virtual layout, you can buy the software and build your own railway. For that matter you might be able to create a virtual imaginary locomotive to run on your virtual model railway.

[PayntersDocks]

5 minutes ago, PhilJ W said:

Quite possible if its a virtual layout, you can buy the software and build your own railway. For that matter you might be able to create a virtual imaginary locomotive to run on your virtual model railway.

Barely have time for the real layout! and thats barely 5' x 2'!

[Michael Hodgson]

It's been done already !

Roger Bannister did the 4 minute mile in 1954 - after BR did it the previous year!

 

 

 

 

1 hour ago, PayntersDocks said:

Now there's an idea for a thread! 1 mile long London Victoria To Brighton Mainline in about 1950 anyone?

Edited September 5, 2022 by Michael Hodgson

[DenysW]

But for WW2 ...

 

Should Turbomotive 2 have been built with more, smaller, driving wheels to improve route availability by bringing the axle loading down from 22.5 tons/axle to 18 tons (as a 4-8-2) with the same 15'3" rigid driving-wheelbase and 4' wheels? Or even to 16 tons as a 4-10-2 and 'tiny' 3' wheels? This assumes leaving a fixed 12" between wheelsets for flanges, brakes, sanding, etc.

 

I'm thinking (based on discussions on the Midland Railway thread) that the reason for big driving wheels on expresses is mostly about how to get steam power efficiently out of reciprocating mechanisms.  I can absolutely see only making very minor changes between 6202 and her conventional sisters, but once proof-of-concept was done, more creativity could have been unleashed.

 

If Turbomotive 2 was also 15" lower (the difference between driving wheel radii), would it have fitted better under overhead power lines, and generally, into the LMS loading gauge?

[Flying Fox 34F]

Have a look at the Chesapeake and Ohio M1 Steam Turbine locomotive. This may have been the way Turbomotive 2 could have gone?

 

Paul

[Compound2632]

1 hour ago, Flying Fox 34F said:

Have a look at the Chesapeake and Ohio M1 Steam Turbine locomotive. This may have been the way Turbomotive 2 could have gone?

 

Certainly steam turbines are more efficient than reciprocating steam engines. But they're not that well-adapted to a locomotive. The logical progression is to have large steam turbines driving generators, with electrical power transmitted to the train via overhead wires.

 

In other words, the true successor of the LMS Pacifics was the BR Class 87.

[Northmoor]

4 hours ago, DenysW said:

But for WW2 ...

 

Should Turbomotive 2 have been built with more, smaller, driving wheels to improve route availability by bringing the axle loading down from 22.5 tons/axle to 18 tons (as a 4-8-2) with the same 15'3" rigid driving-wheelbase and 4' wheels? Or even to 16 tons as a 4-10-2 and 'tiny' 3' wheels? This assumes leaving a fixed 12" between wheelsets for flanges, brakes, sanding, etc.

 

I'm thinking (based on discussions on the Midland Railway thread) that the reason for big driving wheels on expresses is mostly about how to get steam power efficiently out of reciprocating mechanisms.  I can absolutely see only making very minor changes between 6202 and her conventional sisters, but once proof-of-concept was done, more creativity could have been unleashed.

 

If Turbomotive 2 was also 15" lower (the difference between driving wheel radii), would it have fitted better under overhead power lines, and generally, into the LMS loading gauge?

It's not so much about efficiency as reducing piston speeds (so that adequate lubrication can be maintained) and reciprocating forces, by reducing the number of oscillations per second.  As was seen on "Blue Peter" at Durham in 1995, a reciprocating steam loco can run at very high wheel speed, but not for very long......

[DenysW]

1 hour ago, Compound2632 said:

... The logical progression is to have large steam turbines driving generators, with electrical power transmitted to the train via overhead wires. ...

Well, yes, no, and maybe. There's massive infrastructure cost in choosing to go electric (hence some de-electrification of long-ish outes in the USA when asset renewal was needed), and there's still a lot of bu$$eration (and some efficiency losses) in wanting to have simple, efficient 3-phase AC motors supplied from a single-phase AC supply. There's also some risk that overhead power lines won't fit into tunnels in the UK loading gauge (as at the Woodhead tunnel), and you need new bores, and the extra cost and delay.

 

So, unless the government is paying, in a competitive market where the required payback times are short, I think I agree with conventional wisdom that you electrify short-haul commuter and the shorter mainlines, and retain carry-their-own-fuel technologies for freight, branch-lines, and the longer mainlines. Nowadays, diesels, HSTs, and small DMUs.

 

3 hours ago, Flying Fox 34F said:

... the Chesapeake and Ohio M1 Steam Turbine locomotive. ...

 

That's a big jump from the Turbomotive concept, because it went steam turbine->Electric Generator -> Electric drives->wheels, instead of steam turbine -> gear-reduction->wheels. I'm suggesting that LMS + their turbine designers were moving in baby steps, and had solved/abated the problem with turbines that they don't vary their power output as readily as reciprocating steam systems. So step 1: take a powerful express design and replace Stephenson thinking with Ljungström thinking. Step 2 (once Step 1 has worked!) go over the design saying "What other changes in thinking does this allow us - as the next baby step?". I'm suggesting smaller wheels to get better route availability as one possibility.

 

 

[Compound2632]

1 hour ago, Northmoor said:

It's not so much about efficiency as reducing piston speeds (so that adequate lubrication can be maintained) and reciprocating forces, by reducing the number of oscillations per second.  

 

Yes, but it's also about the rate at which steam can be admitted to the cylinder. That's what @DenysW was driving at.

[The Johnster]

The M1 was described at the time as a locomotive that carried it's own power station with it, fundamentally correct.  The most efficient way to power locomotives is probably to use relatively small wheels powered by electric traction motors (for the sake of the discussion we will discount hydraulic transmission as something else for now, though of course it is a perfectly cromulent method).  Large driving wheels are used to reduce piston speed in view of the limitations of lubricants used in the open air while maintaining decent express train speeds; Bullied's leader was in part an attempt to overcome this problem by enclosing the motion in an oil bath, but was not a success, nor ultimately was his oilbath valve gear on the pacifics.  The future, in the 40s and 50s, looked very much like keeping lubricants away from the open air, which was problematic with reciprocal steam or the Turbomotive setup.

 

Turbomotive and similar machines are a step away from Stephensonian reciprocal steam power, which is alleged to be inefficient because of it's thermal inefficiency; too much of the heat you consumed expensive fuel to produce is wasted up the chimney, (though this discounts the advantages of steam's expansive capability and the ability to mortgage the boiler for short periods if needed.  Once a diesel or electric loco is at full power, that's it there's no more and some will overload if you try it in some circumstances).  The problem is that turbines do not perform efficiently if you constantly change the load and power setting for them, as you have to on a railway locomotive; they are fine in power stations or driving ships where the load and settings can be left for long periods.  In railway locos, they burn excess fuel and present maintanence issues.  It is significant that Turbomotive's regular duty was the 10.00 Liverpool-Euston, a heavily loaded non-stop run recognised as one of the toughest firing jobs in the country, where the turbine could be allowed to develop constant full power, and that it was rebuilt as a conventioal Princess Royal, suggesting that while it had been successful as a turbo in that it worked fine, the advantages were not economically worth pursuing.

 

This is an important point; locomotives have to pay their way by pulling trains to time while using the least possible fuel, and what the designers and engineers can provide might be impressive and wonderful, and certainly worth trying out, economic viability is the bottom line.

 

The next step is to isolate the driving wheels from the turbine, and replace the gears with a  turbine driven generator that powers traction motors, these traction motors being fundamentally the same same as those on diesel-electric locos.  By now your locomotive doesn't look like a steam loco any more, and work is being done on fundamentally similar gas turbine setups.  The reason for inserting a generator is that your turbine, steam or gas driven, can run efficiently at a constant speed while the jenny acts as a dampening device for the power supplied to the traction motors, enabling the driver to alter the amperage to them without disturbing the even tenor of the turbine's efficiency.  It works, but it's heavy, noisy and you are constantly worried about the amount of fuel you are burning without it directly leading to pulling the train, back to the reciprocating steam thermal efficiency problem.

 

So, why not produce the electricity at power stations, which you are doing already in any case, and provide it to the traction motors from overhead wires fed from the National Grid?  The tech for driving trains in this way is well-established, though in most previous cases the railway has provided it's own power generation; it's mostly a matter of switchgear and rectifiers.  It's pricey in terms of initial capital investment, but if the traffic demands warrant it and you can get the money out of the Treasury (blood out of a stone), it ticks all the boxes. 

 

Where you can't prise the wonga out of the Treasury or political interference prevents it, but you want to get rid of reciprocal steam because the chattering classes tell you it's old fashioned, you can use diesel-electrics, in which the amps are provided to the traction motors by a diesel engine and main generator on board the loco performing the function of the National Grid and OLE.  Such locos are heavy and not as cost effective as your pure electrics, and are a bit feeble above 100mph, but not everywhere has the traffic to justify the cost of OLE.  There is an alternative, hydraulic transmission, which is a bit lighter on the axles, but you've overdone the power/weight ratio deal and can't shoehorn in airbrake equipment on any of them but the Westerns, and you can't put eth/airco on those.  If you make them powerful enough (not easy in the early days) they can have enough surplus horses to manage eth and airco so long as you can limit the load to about 10 coaches, but don't worry, it's the 70s and traffic is down anyway.  By the time motorway gridlock and petrol prices send it back up again, more powerful electrics and the HSTs are available

 

This is pretty much the development history of UK railways since the 1955 decision to scrap reciprocating steam to the present situation.

[DenysW]

8 minutes ago, The Johnster said:

... Where you can't prise the wonga out of the Treasury or political interference prevents it ...

I note how much OHP-enabled traffic passes through Cardiff. None whatsoever. I note exactly the same about Leicester. {My gast was flabbered by seeing the overhead pylons reach Market Harborough station - the cables have yet to be afforded.} The line from Nuneaton to Coventry (potentially joining up the two legs of the WCML for emergency use) have not been electrified.

 

This is is why I'm sarcastic/depressed about assertions that just because OHP electrification is the best answer to rail travel it will happen in my lifetime.

[Compound2632]

2 minutes ago, DenysW said:

This is is why I'm sarcastic/depressed about assertions that just because OHP electrification is the best answer to rail travel it will happen in my lifetime.

 

One only has to look at the railways on the other side of the channel...

[tythatguy1312]

I'm honestly rather unsure if coal-fired fire tube boilers were even suitable for turbine locomotives, given the issues with thermal efficiency, as well as the problems with reliability on turbine-electric locomotives due to coal dust fouling the motors. I rather believe that the General Electric turbines had more potential than other examples, despite being plagued by poor reliability and specialised maintenance requirements. That being said, I'm not blind to the fact that electrification is a far better idea than messing around with Turbines.

Edited September 9, 2022 by tythatguy1312

[BernardTPM]

There had been steam turbine-electrics before the Turbomotive; the direct drive cut out the losses from making electricty before applying it to the wheels. The later Gas turbine GT3 was similar, again after they'd tried gas turbine-electrics. Neither were repeated, but no doubt added to the sum of knowledge.

[DenysW]

1 hour ago, tythatguy1312 said:

... as well as the problems with reliability on turbine-electric locomotives due to coal dust fouling the motors. ...

I'm a little puzzled by this as I thought the fire/smoke/dust/cinders progressed through heat exchanger tubes towards the exhaust via the chimney. The water (and with superheaters, the initially-wet steam) sat around the other side of the tubes, not meeting the muck until they'd done their work and were ejected via proprietary widgets to provide a driving force to suck air through the coal bed towards the exhaust.  So the dirty and clean sides were kept separate until washdown/maintenance/etc.

[DenysW]

1 hour ago, BernardTPM said:

... There had been steam turbine-electrics before the Turbomotive; the direct drive cut out the losses from making electricty before applying it to the wheels. ...

It also cut out the weight and complexity of steam->electricity->drives. It left you with overcoming the point that @The Johnster makes, that turbines are not equally good at every speed, they have an optimum rpm, and thus, with fixed-gearing* steam locomotives, an optimum speed. I think we just don't know whether Turbomotive was put on the toughest duty in LMS because it could be trusted to do it, or because it couldn't be trusted to do more variable duties efficiently/effectively. I suspect the former, and regard the latter as somewhat unproven. But I've done an embarrassingly little amount of research before reaching this position.

 

*I shudder at the thought of having the task of developing synchromesh in the 1930s to apply gearing to 2,000 hp steam engines driven by men more used to getting there on time than protecting the mechanisms.

[DenysW]

2 hours ago, Compound2632 said:

One only has to look at the railways on the other side of the channel...

On p18 on "Beyond Dover" in Overseas modelling (posted by @TT-Pete) there's a 1950s propaganda (= one-sided) clip about the French electrifying their network. It's pretty convincing until one realises that this is why Chapelon was unpopular with the French railway establishment: his belief and track record showed you could get a lot more out of upgrading existing steam - and this (at best) undermined the official case, and at worst sent it back to the drawing board. Not automatically wrong. Just needing a lot more, more careful, thought.

 

It also helps explain TGV to me: the French government is used to the (nationalised in 1938) railways being a black hole into which you throw capital money, resulting in jobs being created/maintained. Stop spending, have unemployment problems.

 

I remember reading that by the late 1950s, 14% of UK government spending was going on the railways. Hence Beeching.