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Imaginary Locomotives


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47 minutes ago, rodent279 said:

Were there any standard gauge double Fairlie's? If not, why not?

I think these were SG, but I'm not too familiar with Mexican Railways.

https://en.wikipedia.org/wiki/Fairlie_locomotive#Mexico

There appear to be some Russian ones as well, presumably broad gauge:

https://en.wikipedia.org/wiki/Fairlie_locomotive#Russia

 

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Rodent279 said "Were there any standard gauge double Fairlie's? If not, why not?"

 

Very few, because they are a bad idea except for short-haul. So suited to the Ffestiniog, but not much else. More specifically:

 

-     The frame was/is rigid for the entire length of both boilers. Even with double-articulation underneath this gets limiting on curves quite quickly as you try and scale-up to bigger locos

-     As tank engines without a rear bunker, the coal is stored on one side. This is awkward for the fireman, and also restricts the amount you can store.

-     As a result there is no tender-version possible, in contrast to pretty much all the other articulated types. Even the Garratts had a South African version with a water-tender as a possibility.

 

 

 

 

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A Double Fairlie has a single firebox (albeit partly divided).  Wouldn't the true IC equivalent be some sort of flat opposed piston design with each crankshaft driving its own bogie? If it were mounted vertically in the middle of the loco, you could replicate the cramped cab of the original too. Or lay it flat and put the poor driver on top - equally unpleasant but better visibility as befits a modern loco.

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This is recollection-time so it's suspect, but here goes ...

 

I thought the early double Fairlies were as Flying Pig says, with a single firebox , but they couldn't get the drafting to work properly enough of the time. So the design was changed to two independent locomotives, still on a single, long, rigid frame.

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1 hour ago, PhilJ W said:

The first one on the N&B was Pioneer in 1865. They weren't very successful due to the shared firebox which caused problems with one boiler being starved of heat. 

 

Some info on Double Fairlies at Festipedia: https://www.festipedia.org.uk/wiki/Double_Fairlie

 

It seems the first one with divided firebox to address unequal draught was the Festiniog's Little Wonder of 1869. 

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6 hours ago, PhilJ W said:

The first one on the N&B was Pioneer in 1865. They weren't very successful due to the shared firebox which caused problems with one boiler being starved of heat. 

I think I read somewhere that the boiler shell of one of the N & B ones still exists somewhere as a storm water culvert in a sea wall in south Wales. I'll have to have a bit of a trawl through the old memory bank.

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On 18/01/2022 at 10:37, whart57 said:

Wouldn't a diesel like this be a logical development for a line with double Fairlies?

 

image.png.d5cb80fb6eff5400a13235ce91276908.png

 

So the imaginary loco is a 2' gauge version of the CIE's West Clare diesels

Arguably any bogie diesel or electric (whatever the gauge) is the direct equivalent of a steam Fairlie, flexible drive units with the power plant on a rigid frame mounted above it.

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2 minutes ago, john new said:

Arguably any bogie diesel or electric (whatever the gauge) is the direct equivalent of a steam Fairlie, flexible drive units with the power plant on a rigid frame mounted above it.

I think that was the start of powered bogies for most diesels back when they were first introduced to present day, the Fairlies also had a hand in the creation of american articulated locomotives as well.

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2 hours ago, Johnson044 said:

I think I read somewhere that the boiler shell of one of the N & B ones still exists somewhere as a storm water culvert in a sea wall in south Wales. I'll have to have a bit of a trawl through the old memory bank.

Mentioned here on RMWeb a few years ago:

 

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Double Fairlies as precursors of bogie diesel locmomotives?  Well, sort of.  The nearest equivalent would, I suppose, be a double engined diesel hydrualic like a Warship or a Western, but would one regard the diesel engine or the Cardan shaft as the equivalent of the boiler?  Or, if you regard the 'engine' of a steam locomotive as the cylinders, pistons, connecting rod, and valves, then the analagy falls down, since those parts in a diesel hydraulic are separated from the driven wheels by the layshaft and gears. not to mention the hydraulic pumps.

 

A diesel mechanical would be a closer approximation but these are not as a rule mounted on bogies, and a diesel electric is something completely different.

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If you regard the firebox, boiler and smokebox as the diesel engine and generator (producing steam instead of electricity) and the cylinders, connecting rods and couping rods as the traction motors and gears (using that steam to create motion), the analogy works.

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Agree. I'd view the firebox as analogous to the engine of a diesel, and the boiler as analogous to the generator. The steam is equivalent to the electricity and the cylinders are equivalent to the traction motors. The valve gear is the equivalent of the control cubicle.

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I go right back to Trevithick’s first concept for what was then high pressure steam, a portable power pack sitting on a frame and able to power a wheeled trolley, drive a pump, wind a winch etc. That evolved into designs with the steam power pack rigidly fixed above the frames. OK later extended with leading and trailing wheels to allow a bigger steam generator but as a concept right through to early shunting diesels with their rigid wheelbase.

 

Various designs of flexible chassis steam engines evolved over time including the design with the bogies, namely the double Fairlies, and Shays etc. Yes the double boiler on a Fairlie was an innovation but I see the twin bogies to be the more significant factor in influencing design of a bogie diesel or electric. With these there is a power pack, just like Trevithick’s idea, taking power down to a pair of driving bogies. However it is powered and geared the bogie is where the raw power, be that steam, hydraulic or electricity drives the wheels. 
 

An 08 ‘Gronk’ therefore owing more in this design concept sense to an early steam engine than the Bo-Bo diesel which has a design conceptual layout owing more to a Fairlie.

 

Edited by john new
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2 hours ago, rodent279 said:

Agree. I'd view the firebox as analogous to the engine of a diesel, and the boiler as analogous to the generator. The steam is equivalent to the electricity and the cylinders are equivalent to the traction motors. The valve gear is the equivalent of the control cubicle.

You can only push analogies so far......

1799135928_24FebKalka6.JPG.8171435945ce0683002e8a659aa33ea7.JPG

Best wishes 

Eric 

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On 19/01/2022 at 02:17, Alex Neth said:

I read somewhere that the proposed Whyte notation for the BR standard 5MTs was 4-6-2, but deemed too large and costly, and so the 4-6-0 design was chosen over it. I made a (real terrible, but tried my best) photoshop of what if the 5MTs were 4-6-2

Adobe_20220118_200552.png

 

Despite looking like a 5MT boiler, that looks like it might work.

 

On 19/01/2022 at 02:21, Ben Alder said:

My almost finished take on a Class Five pacific with smaller drivers.

 

IMG_1912.JPG

Which boiler are you using, it looks like the Clan boiler?

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On 22/01/2022 at 06:07, Traintresta said:

 

Despite looking like a 5MT boiler, that looks like it might work.

For the edit I used a clan boiler, even though I wanted to use a slightly extended 5MT boiler.

Edited by Alex Neth
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I know discussion of this particular class is often rather fiery due to... everything but I'm rather curious as to how one should go about fixing the E2's. Based on driver reports, I suspect an issue with excessive drafting was the cause, as they tended to throw burning coal out the chimney when the regulator was wide open. Could a redesigned smokebox have fixed this?

E2.jpg

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1 hour ago, tythatguy1312 said:

I know discussion of this particular class is often rather fiery due to... everything but I'm rather curious as to how one should go about fixing the E2's. Based on driver reports, I suspect an issue with excessive drafting was the cause, as they tended to throw burning coal out the chimney when the regulator was wide open. Could a redesigned smokebox have fixed this?

E2.jpg

I would think so, but another part of the problem was that the E2s had the I2 boilers, which in turn were real sh*tty. Always having the boiler pressure drop right as you get it up to where it needs to be. 

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7 hours ago, tythatguy1312 said:

I know discussion of this particular class is often rather fiery due to... everything but I'm rather curious as to how one should go about fixing the E2's. Based on driver reports, I suspect an issue with excessive drafting was the cause, as they tended to throw burning coal out the chimney when the regulator was wide open. Could a redesigned smokebox have fixed this?

E2.jpg

Why do you want to fix it?  The E2 was intended as a shunting tank, and, with 4' 6" diameter wheels, it seems a rather rash experiment to see whether it might work as a commuter train loco, when a wide open regulator would be required.  They weren't even superheated, which might have helped the situation.

Interesting photo though, as it appears to have only four head-code irons, missing the ones that should be on the smokebox door.

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12 hours ago, Alex Neth said:

was that the E2s had the I2 boilers, which in turn were real sh*tty

I did get curious about that, and I found that at least a few E4’s also used the I2 pattern boiler yet turned out significantly more successful. I’m at a loss as to why or how, but their higher coal/water capacity might’ve mitigated the issues that lead to its inefficiency

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