Modern steam: adventures in freelance loco design

[Guest]

I'm in a "what if" mood. Yeah, okay, I've always been in a "what if" mood. So sue me. For some years, now, I've been wondering how things might have been if the Great Diesel Con-Trick had never happened steam hadn't died. So there's my starting point. But what next?

 

I'm learning CAD, and as I'm sure anyone else similarly engaged will tell you, it's great fun. Hard going but great fun. I'm acquiring new skills all the time, doing things with a computer that I'd never actually thought possible (ribald comments at this juncture will be ignored). Given that, this is what I've come up with so far - just a start, admittedly, but ongoing. What I plan to do with it once finished, I'm not sure. It's been engineered to be 3D Printed and that remains an option. Having said that, the cost of this (very much unfinished) loco body alone already works out at about €50 in Shapeways FUD, and it's not exactly the biggest design I have in mind. But the STL file is viable, that's the main thing I wanted to prove by uploading. Decision time, fortunately, is some way off.

 

So this is it, an 0-8-0T shunter. Continental loading gauge restrictions apply: think 13'9" by 9'9". Very conventional in outline but containing a few modern refinements. The first will be found in the driving wheels, being of Boxpok pattern.

 

 

The body really is conventional but I don't have a problem with that: I want this to look like a steam loco, not a Leader knock-off. And frankly, given its simplicity and general ruggedness, plus its ability to carry on even in a run down condition, the reciprocating steam locomotive still has a lot going for it.

 

 

 

More will follow. After the body is completed, the chassis, and I think things will get a little easier with that.

[34theletterbetweenB&D]

Got to tackle the 'ease of servicing' issue of steam vs diesels.  A shorter side tank from forward of the firebox means all the firebox  water space accesses are available for wash out and inspection without lifting the side tanks off. Since this class of loco is typically a yard shunter, small water capacity is probably not that important.

[newbryford]

Although the curves on the water tanks may look nice, they would be far more complicated (i.e. expensive) to produce in sheet meta in full sizel. Unless you're considering using glass fibre mouldings maybe to save weight????

Likewise as per 34C's post for maintenance, no forward running plate to allow acess to the fiddly bits. GW 15xx style?

Cheers,

Mick

[Guest]

Got to tackle the 'ease of servicing' issue of steam vs diesels.  A shorter side tank from forward of the firebox means all the firebox  water space accesses are available for wash out and inspection without lifting the side tanks off. Since this class of loco is typically a yard shunter, small water capacity is probably not that important.

 

I take your point but I can't see this. In the days of steam, washouts could be as frequent as once a month. Did they really have to dismantle the thing every time? The few narrow firebox diagrams of any real detail that I've seen show the mudholes at the bottoms of the backplate and outer throatplate. Since these would be between the frames, access would be no problem: just put the loco over a pit. As an aside, I once saw on the 5AT website a picture of a projected 2-8-4T (can't seem to find it now). I presume they would have addressed this question if they'd done any detail design work but there was no suggestion of shortened side tanks there. I feel the urge to e-mail someone coming on...

 

On a more general point, assume widespread use of TIA or a developed version such as PT. Washout frequency can be reduced to as little as once every 90 days with scope for further reduction. Also, when washouts actually have to be done, assume the use of the 'hot' method rather than the 'cold'. The loco will out of traffic for hours rather than days and thermal stressing of the boiler will be avoided.

 

You raise a good point and I do thank you for it but I think this one is covered.

 

Although the curves on the water tanks may look nice, they would be far more complicated (i.e. expensive) to produce in sheet meta in full sizel. Unless you're considering using glass fibre mouldings maybe to save weight????

Likewise as per 34C's post for maintenance, no forward running plate to allow acess to the fiddly bits. GW 15xx style?

Cheers,

Mick

 

Fibreglass? Er...no. There is a reason for the curves but I'm damned if I'm entirely certain what it is. Let me explain. I actually borrowed the idea from the Algerian 241+142YAT class. These radiused edges and corners also appear on French designs like the 141TC and 141TB. I think they have something to do with the inherent rigidity of tubular elements in structures - that is, they're there to make the tanks more rigid, less prone to flexing. As for manufacture...well...we've come along a little in metal fabrication skills since anyone last built a tank engine. I'm not worried about that one. So no, until I'm corrected on my assumptions, the curves stay.

 

Running plates - yes, I know of the lack of them on the 15xx and used to wonder about that. You see, everything being on the outside, I can't see what they would actually be hiding. I also used to wonder what the enginemen would stand on when trying to lift the filler caps to water the thing. No, I'm going to give my crews some help and leave them there.

 

Again, thanks for your input - indeed, to both of you. Makes me go back and double-check what I'm doing. 

[Guest]

Some progress on the general arrangement. I am working to a diagram, be it noted, one I produced in 2D using Paint. Nice to get something more solid to look at, though.

 

 

 

 

Yeah, I know what you're thinking: that overhang front and rear looks a bit excessive. Actually, it's within a few inches of that found on another and more well-known 0-8-0T, a Maunsell Z. Nature of the beast, I'm afraid.

 

[Gordon A]

Full outside valve gear, Walscherts (cant spell) Mechanical lubricator, and external oil boxes. There should be no reason to go between the frames on a daily basis.

(Thats why I like driving Karel our Polish tank engine!)

A hopper ash pan and a smaller version of the British Railways rocking grate?

Cab side windows that slide?

On the front you need somewhere for the crew to stand clean out the smokebox?

How are the crew supposed to get at the coal in the bunker to make sure that there are no empty spaces left when coaling?

Small central doors in the back of the cab?

Comfortable and practical seats for the crew and a tool box.

Had you considered sloping the fron tops of the tanks like the GWR 4575 tanks for improved buffering up visibility?

 

Gordon A

Bristol

[Guest]

One thing at a time, Gordon.    It's still early stages and I have yet to get the big stuff in place before considering the details. They will come - and no doubt in line with what you list. I'll even include a shelf for the crew to put their tea on.

 

Cylinders and valve gear will indeed be outside. Where else would one put them on a modern loco? As for that valve gear, I'm great fan of keeping inlet and exhaust functions separate so poppet valves beckon. Cossart? And incorporating some measure of reciprocating balance in the valve motion, as per usual practice with that gear? Or would that be necessary on an engine intended to do most of its work at low speed? Hammer blow ain't exactly going to be a problem. I dunno. Time enough yet for thinking about that one.

 

Tapered tanks. Hmm. Yeah. Good point...

[peach james]

OK- so...

 

plus its ability to carry on even in a run down condition, the reciprocating steam locomotive still has a lot going for it.

 

NO  If you don't take anything else from reading Red Dragon, then this is it- yes, an engine will run in bad shape.  But it _should never_ be run in that state. 

 

Valve gear: Franklin RC would be the "best" if the engine is going to be used in conditions which would warrent it's use.  Shunting is NOT one of those cases- Walscharts is simpler to make, and works.  There is a level of engineering which is appropriate to the job.  Real sophistication isn't the design goal here, but an engine that will do what it needs to do as cost effectively as possible is.  Insulate.  Add a feedwater heater.  Encourage setup for 2 person total operation.  Ease of maintenance is of vital importance- because, if you can fix it then it will get fixed, and if not, then it will get left forever in the "too difficult" pile. 

 

Also, teach the drivers the understanding of why.  Why is excess air bad?  Why does the insulation need to be effective?  What happens in the cylinders?.  It's not a no-brain operation with steam. 

 

I'm playing with a design in conversation with my dad- eventually, the idea is to build a IMLEC competetive loco.  It currently consists of a series of EXCEL spreadsheets, and a bit of math.

 

James

[Gordon A]

As the design is for a shunting loco, you need to have lever reverser not a screw reverser (The one fault on Karel) so I would reccomend nothing fancy in the valve department.

 

Gordon A

Bristol

[Guest]

OK- so...

 

plus its ability to carry on even in a run down condition, the reciprocating steam locomotive still has a lot going for it.

 

NO  If you don't take anything else from reading Red Dragon, then this is it- yes, an engine will run in bad shape.  But it _should never_ be run in that state. 

 

Valve gear: Franklin RC would be the "best" if the engine is going to be used in conditions which would warrent it's use.  Shunting is NOT one of those cases- Walscharts is simpler to make, and works.  There is a level of engineering which is appropriate to the job.  Real sophistication isn't the design goal here, but an engine that will do what it needs to do as cost effectively as possible is.  Insulate.  Add a feedwater heater.  Encourage setup for 2 person total operation.  Ease of maintenance is of vital importance- because, if you can fix it then it will get fixed, and if not, then it will get left forever in the "too difficult" pile. 

 

Also, teach the drivers the understanding of why.  Why is excess air bad?  Why does the insulation need to be effective?  What happens in the cylinders?.  It's not a no-brain operation with steam. 

 

I'm playing with a design in conversation with my dad- eventually, the idea is to build a IMLEC competetive loco.  It currently consists of a series of EXCEL spreadsheets, and a bit of math.

 

James

 

Okay, points in order. I totally agree with you about not letting an engine get run down. My point was that, by and large, it remained fairly reliable when it did so, which happened rather more often than was desirable in the days of steam - especially towards the end. Steam can be kept in excellent shape and very efficiently, too. You only have to look at the facilities provided by the Norfolk & Western to see that. No, I take your point. Mine was for the purposes of illustration, not intent.

 

Having read up a little more on Porta's work with piston valves, I'm inclined to agree with you on the questions of valves and valve gear. I simply hadn't realised the development had got so far with piston valves. I'm looking again at this question but I have the sneaking suspicion you may be right.

 

Education. Can't disagree with you about that: steam never has been and never will be a no-brain operation. I have to admire the French in this respect. The training of their crews was exemplary.

 

I'm familiar with IMLEC and wish you well. You are, of course, most welcome to keep us informed of your progress on this forum! I'm sure you will gather a very interested audience.

 

As the design is for a shunting loco, you need to have lever reverser not a screw reverser (The one fault on Karel) so I would reccomend nothing fancy in the valve department.

 

Gordon A

Bristol

 

Lever reverser already factored in, Gordon. Screw reverse is not something I would inflict on any shunting crew where the engine spends most of its time in full forward gear then full back then full forward then - repeat ad nauseam. Did anyone ever try some sort of power-assisted reverser, I wonder?

Edited July 23, 2013 by Guest

[Gordon A]

A number of British locos were / are fitted with steam reversers.

 

One of the negative comments was that they could creep from midgear to a positive direction.

Or if the crew were not used to a steam reverser the fireman accidently turning off the steam supply to the reverser, leaving the driver scratching his head for a while.

 

Gordon A

Bristol

[Guest]

This should improve crew visibility.

 

[Gordon A]

Yes, the driver stands a chance of seeing the buffers meet at the front end, the rear end is not so bad as he can stick his head out of the cab and see the rear buffers.

 

Gordon A

Bristol

[34theletterbetweenB&D]

...Cylinders ... will indeed be outside. Where else would one put them on a modern loco? ...

In the scrap bin. A truly modern steam loco should have a Wankel rotor layout engine; probably needs a small reciprocating 'donkey engine' to push it off in the right direction as I doubt it would be self starting. Rotary sleeve valve admission and exhaust of course. No dynamic balance problems at all, so the axle loading can be maxxed out for best adhesion to enable the largest starting tractive effort to be deployed. This is so far out I am amazed that Oliver Bulleid never thought of it. Or perhaps he did but the directors of the Southern Railway concealed the evidence.

[Mark Dickerson]

It would appear a Professor Borst might win on "far out" steam http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=4043248

 

I don't know if the X-12 would count as Real Steam in the OP's view though (although you'd get a readout ). I'm still not sure it's for real - but that's the Fifties for you...

 

 

[HSB]

It would probably have gone like a bomb! 

[Tiptonian]

Can't see a reason why even a single rotor Wankel steam engine would not self-start. With two lobes on the outer casing and three flanks on the rotor, there are six power strokes per revolution, each stroke effective for nearly one quarter of a revolution, but yes, it would be better with two rotors. Also, it does not require admission and exhaust valves as such, as the movement of the rotor carries the steam round with it, passing ports in the outer casing as it travels round. Admission would be by a series of side and peripheral ports (small side ports for the equivalent of short cut-offs, a large peripheral port for maximum admission), The cut-off lever would open valves in an "induction manifold", thus determining which ports receive steam. If a reversing gearbox was felt undesirable, all ports could be mirrored for reverse operation, thus the large peripheral port forward would become the exhaust port reverse, the steam path again being determined by the cut-off / reversing lever. As fascinating as this is, after low mileages it would probably leak like a Leader!

[Guest]

So I'm back from a weekend acting as road crew for my wife while she did a couple of medieval-style music performances in Kerteminde. Hot. And made doubly so by having to cart around medieval flutes, big drum, bagpipes and costumes. She's a trained soprano but covers the middle ages and Renaissance periods, too. Me? I'm a Heavy Metal man. We do not see eye-to-eye on music...

 

In the scrap bin. A truly modern steam loco should have a Wankel rotor layout engine; probably needs a small reciprocating 'donkey engine' to push it off in the right direction as I doubt it would be self starting. Rotary sleeve valve admission and exhaust of course. No dynamic balance problems at all, so the axle loading can be maxxed out for best adhesion to enable the largest starting tractive effort to be deployed. This is so far out I am amazed that Oliver Bulleid never thought of it. Or perhaps he did but the directors of the Southern Railway concealed the evidence.

 

Sorry, no. I have my doubts about the torque of a rotary engine in such applications. I'm talking about turning movement, the sheer low-end grunt that takes a reluctant train by the scruff of the neck and gets it moving. Yes, you can use gearing but you start to get away from steam's sheer simplicity, and that I do not propose to give up. 

 

In his excellent book, Living With London Midland Locomotives, A.J. Powell put forward a proposal for a rebuild of the Jinties using Sentinel power plants connected to the driving wheels by gears. That, I think, is about as far as I would be prepared to go in abandoning the conventional form, and even then, there would have to be some b****y good reasons for doing so.

 

Can't see a reason why even a single rotor Wankel steam engine would not self-start. With two lobes on the outer casing and three flanks on the rotor, there are six power strokes per revolution, each stroke effective for nearly one quarter of a revolution, but yes, it would be better with two rotors. Also, it does not require admission and exhaust valves as such, as the movement of the rotor carries the steam round with it, passing ports in the outer casing as it travels round. Admission would be by a series of side and peripheral ports (small side ports for the equivalent of short cut-offs, a large peripheral port for maximum admission), The cut-off lever would open valves in an "induction manifold", thus determining which ports receive steam. If a reversing gearbox was felt undesirable, all ports could be mirrored for reverse operation, thus the large peripheral port forward would become the exhaust port reverse, the steam path again being determined by the cut-off / reversing lever. As fascinating as this is, after low mileages it would probably leak like a Leader!

 

Largely agreed on your last point. I have wondered why Bulleid stayed with the conventional form of drive (probably the war years and therefore shortages) when he must have been aware of a B&O proposal using Besler steam motors. I think he would have liked that one.

[HSB]

 

 

 

 

In his excellent book, Living With London Midland Locomotives, A.J. Powell put forward a proposal for a rebuild of the Jinties using Sentinel power plants connected to the driving wheels by gears. That, I think, is about as far as I would be prepared to go in abandoning the conventional form, and even then, there would have to be some b****y good reasons for doing so.

 

 

There were some mainline Sentinels with conventional boilers running on Egyptian Railways (I have a picture in a book somewhere!). I don't know how successful they were.

Edited July 23, 2013 by HSB

[Guest]

You piqued my interest, Howard, so I Googled that one. What I got was this. Fascinating stuff and thank you for the prompt. I will be taking a closer look at this one.

 

You know, steam locomotive history is full of intriguing might-have-beens. Take Paget's multi-cylinder loco. A little more development and ditching of that ridiculous dry-back boiler (with grate area of 55sq.ft. and two firehole doors - I ask you!) and he might have had something there.

[69843]

It would appear a Professor Borst might win on "far out" steam http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=4043248

 

The fallout in the press would be enoumous if it ever crashed....

[Alastair-I]

How modern is "modern" in this context? - so far it looks like end-of-steam plus a bit, which I admit will make it "modern image" for some.

 

If we're talking post-2000 (or even post-1980), then one-man operation should be the goal and do away with the fireman.  Computer controlled systems would look after adding fuel (lumps or coal granules/dust? - assuming it's not LPG or kerosene) and water.  The cab is likely to be fly-by-wire, possibly twin cab for shunting with a control point on each end.  Keep your cab-end where it is (but the operators area will be drastically reduced to make room for the automatic controls), but with another at the other end (minus bunker).  The forward cab can hinge downwards or sideways for access to the smoke box.  For that matter, side tanks could hinge downwards for access when empty (assuming automatic washout facilities can't be designed to operate from between the tracks).  Ease of use (one man operation, automatic systems, driver visibility), cheapness of manufacture and ease of maintenance (access, symmetry and interchangability - e.g. identical side tanks left and right) are the primary design criteria.

 

Just my two pennyworth, YMMV.

Edited July 23, 2013 by Alastair-I

[Colin]

The design's attractive and looks a bit French to me, I'm not quite sure why.

IMHO with a couple of bogies added it would make a very nicely proportioned 2-8-2T; that would also remove the big overhang at both ends .

Other possibility might be make it into an 0-10-0T, think DB BR94.

[scots region]

Hi David, would it be possible to incorporate pre heaters into the tanks? Also the 2-8-4T your were referring to was proposed as an alternative to 5AT.

 

 

Its called 8ATT, it was aimed as an testbed for 5AT on preserved railways I do in fact think this would be a better option to pursue. 

 

 

Here's its 2-8-0 blood relative. 

[Gordon A]

If you add preheaters to the water tanks you could get problems with conventional injectors which require cold water to work.

One in jector could be replaced with a pump on the running plate.

 

Gordon A

Bristol