Imaginary Locomotives

[rodent279]

3 minutes ago, cctransuk said:

 

Perhaps we need a new thread entitled 'Fantasy / Nightmare Railways'?

I come here to get away from the real world......

[CaledonianYank]

17 minutes ago, cctransuk said:

 

With all due respect, there seems to be some confusion / misunderstanding about the UK  designations of branch line and tramway.

 

These descriptions are not official categories/ designations. Tramways were either : -

 

a] what are known in the USA as streetcar lines; essentially street railways for passenger traffic, usually horse or electric powered;

 

b] very basic, minimally engineered light railways for areas where traffic would be either very light or for a specific industrial purpose.

 

Neither type would require or justify complex propulsion systems - basic blacksmith technology would be the order of the day.

 

Perhaps we need a new thread entitled 'Fantasy / Nightmare Railways'?

 

CJI.

Im american and do primarily Scottish, Welsh, Cornish, and English style modeling. Unfortunately, despite that being the stuff I focus on, am not an expert on these things. Thank You for bringing that to my attention though. Ardarffahr Light Railway didn't feel exactly right to me though

[rockershovel]

1 hour ago, CaledonianYank said:

The decapod is intended to work as a banker on the steepest part of the line. The tramway uses mainline track and has decent curves. Due to space constraints on the open line, it cannot upgrade to a branchline

 

Perhaps the carriages and engine would power air compressors to enable the function of the final carriage. It should be remembered that the carriages are former non-bogie coaches from the GWR, LBSCR, MR, HR, CR, and other such pre-grouping railways.

 

Most of the engines with lead/drive wheels are capable of diverting steam to cylinders to drive those wheels if ever necessary, the singles being exceptions

 

The engines aren't narrow gauge as the line needs to carry too much material to justify building them as so, at least when the tramway was first opened.

I have to say, a tramway or light railway requiring an 0-10-0 as a banker seems a stretch too far for credibility .. 

[rodent279]

1 hour ago, rockershovel said:

I have to say, a tramway or light railway requiring an 0-10-0 as a banker seems a stretch too far for credibility .. 

It's an entertaining idea, if nothing else. Rule 1 and all that ....

[JimC]

2 hours ago, rockershovel said:

I have to say, a tramway or light railway requiring an 0-10-0 as a banker seems a stretch too far for credibility .. 

I suppose if one imagines heavy traffic and a harsh axle loading limit on a light railway then an 0-10-0 could have light axle loading. Over bridges might be an issue!

Here's a *very* quick hack - a Dukedog boiler on ten 1361 wheels. A Dukedog weighed 49 tons, so might we imagine an axle weight of under 10 tons per axle? Might have to have an 8 wheeled tender!

Edited November 26, 2022 by JimC
Added sketch

[rodent279]

Though I'd imagine a light railway might be more likely to go for a stretch of rack & pinion to help with a steep gradient. Seems to work OK on the Berner Oberland Bahn in Switzerland. 

Edited November 27, 2022 by rodent279

[burgundy]

The idea of a ten coupled loco on a minor railway is not so far-fetched if you look at the railways in Saxony. Class VI K is a ten coupled tank loco weighing in at a little over 40 tons. If you want something a bit more "modern image", how about a tender loco built in 1939 where the loco weighs under 30 tons.

Best wishes 

Eric 

[Northmoor]

11 hours ago, JimC said:

I suppose if one imagines heavy traffic and a harsh axle loading limit on a light railway then an 0-10-0 could have light axle loading. Over bridges might be an issue!

Here's a *very* quick hack - a Dukedog boiler on ten 1361 wheels. A Dukedog weighed 49 tons, so might we imagine an axle weight of under 10 tons per axle? Might have to have an 8 wheeled tender!

This is why - Rule One notwithstanding - it is probably a bit too fanciful; if the traffic (probably freight). was that heavy then It either wouldn't have been built as or remained a Light Railway.  The company building the line would have been able to justify heavier engineering in the first place, or invested to strengthen the infrastructure on the profits from the heavy traffic. 

[rodent279]

1 hour ago, burgundy said:

The idea of a ten coupled loco on a minor railway is not so far-fetched if you look at the railways in Saxony. Class VI K is a ten coupled tank loco weighing in at a little over 40 tons. If you want something a bit more "modern image", how about a tender loco built in 1939 where the loco weighs under 30 tons.

Best wishes 

Eric 

Slightly larger & heavier, but still with an axle load of just under 10t, are these impressive East German 2-10-2T's.

 

https://en.m.wikipedia.org/wiki/DR_Class_99.23-24

 

I like the idea of a 2-10-2T on metre gauge.

[tythatguy1312]

5 minutes ago, rodent279 said:

I like the idea of a 2-10-2T on metre gauge.

you should see what the Letterkenny & Burtonport railway got up to, though these titans are normally associated with the Londonderry & Lough Swilly Railway.

[rodent279]

1 hour ago, Northmoor said:

This is why - Rule One notwithstanding - it is probably a bit too fanciful; if the traffic (probably freight). was that heavy then It either wouldn't have been built as or remained a Light Railway.  The company building the line would have been able to justify heavier engineering in the first place, or invested to strengthen the infrastructure on the profits from the heavy traffic. 

I suppose heavy traffic could have developed unexpectedly after construction,  say because a mine, power plant, steel works etc opened at some point.

[rockershovel]

The South African 2' gauge 2-8-2s aren't small, either. 

 

It's the "banker" thing which somehow doesn't fit, for me. 

[JimC]

5 hours ago, Northmoor said:

if the traffic (probably freight). was that heavy then It either wouldn't have been built as or remained a Light Railway.

Fair comment. To put it in proportion though, big as it superficially looks, with 50 tons of adhesive weight it can't be much more powerful than a GWR pannier tank. We have to imagine a long light railway for such to be a useful proposition. As pointed out above very light axle weights were something of a feature in parts of Germany and Austria.

[Miss Prism]

Hungarian narrow (760mm) gauge

[AlfaZagato]

Honestly, it does only seem to be the UK and the US that tried to keep axle counts to a minimum.    Need we discuss the Soviet 4-14-4 again?

[DenysW]

5 hours ago, AlfaZagato said:

Honestly, it does only seem to be the UK and the US that tried to keep axle counts to a minimum

It seems to be a battle between route availability based on maximum axle loading, and route availability set by track curvature giving a maximum rigid wheelbase. So the first is pushing towards more axles and the second is forcing that choice to mean smaller wheels and lower speeds.

 

The UK and the US don't seem to have loved any of the proprietary axle designs that attempted to make the 'rigid wheelbase' bit less restrictive. 

 

The Soviet 4-14-4 night have worked as a 4-7-7-4 on this basis, but seems solely to have been the result of a "My engine's got more axles than your engine" futile pissing contest.

[JimC]

6 hours ago, AlfaZagato said:

Honestly, it does only seem to be the UK and the US that tried to keep axle counts to a minimum.   

I suspect economic factors at work.. This is pure guesswork, those who know more correct me, but did the US had plenty of cheap steel and perhaps relatively few bridges, so could have heavy rails for their large but infrequent trains? 

And did the UK have short distances, lots of curvature and frequent trains, which meant stations (=revenue earning points) were not far apart so earning per mile track was good? 

By contrast might one expect long distances and expensive steel to make lighter trackwork more compelling? 

This is very much off the cuff rambling, its not researched in any way. Who knows better? 

[Compound2632]

On 26/11/2022 at 14:07, DenysW said:

Reciprocating locomotives needed most/all of the steam to exhaust via the smoke box to suck air through the fire. Read about the Erie triplexes, and the difficulties of Kitson-Meyers.

 

That's why the blower was invented - to maintain draught when there was insufficient exhaust steam blast to create an adequate vacuum in the smokebox, such as when stationary.

 

So soft draught is not an issue in this case (though there are plenty of other issues) and ought not to be a problem for a compound, either.

[tythatguy1312]

6 hours ago, AlfaZagato said:

Honestly, it does only seem to be the UK and the US that tried to keep axle counts to a minimum.    Need we discuss the Soviet 4-14-4 again?

bold of you to assume we did. Let's be honest the LMS Garratts and the LNER J70's were overbuilt. The Garratts were absolutely gargantuan machines for work that a large 2-8-0 could do and the Wisbech & Upwell Tramway barely demanded a 6 coupled machine

Edited November 28, 2022 by tythatguy1312

[Compound2632]

39 minutes ago, tythatguy1312 said:

the Wisbech & Upwell Tramway barely demanded a 6 coupled machine

 

On the contrary, Holden introduced the C53s because the Worsdell G15s were unequal to the W&U traffic by the early years of the 20th century; the C53s also worked various docks: 

https://www.lner.info/locos/J/j70.php.

Edited November 28, 2022 by Compound2632

[DenysW]

4 hours ago, tythatguy1312 said:

The Garratts were absolutely gargantuan machines

As per recent posts on this thread, the LMS Garratts were (almost exactly) two LMS 4Fs in terms of grate area and boiler capacity, and that's what they were intended to replace. So a 2-8-0 could do the same 90(ish) loose-coupled, unbraked coal wagons only if it could start them up against the ruling gradient (lots of starting tractive effort), and then trundle them along at 15-25 mph (moderate power). I suspect that the latter is true, but not the former. I have an open mind about the ability of the LMS Garratts to brake those same loaded coal wagons downhill against much more than the same 1:100(ish) ruling gradient that is Toton-Brent, and zero confidence in a 2-8-0 as an effective brake in this duty. I note the Garratts started out with brakes on the non-driving wheels (as well) but that these were later removed (once their uphill limits had been empirically established?).

[Compound2632]

11 minutes ago, DenysW said:

the same 1:100(ish) ruling gradient that is Toton-Brent

 

The stiffest climb for a southbound (i.e. loaded) train was the four miles or so at 1:132 / 1:133 up from Market Harborough to Desborough, and from the point of view of braking, the similar grade coming down the other side to Kettering. The goods lines at Sharnbrook (avoiding banks at 1:120 on the original Leicester & Hitchin line, built when money was tight) were laid out at 1:200 up from Wellingborough then dropping at 1:160 towards Bedford. I think that indicates the relative importance of haulage power vs. brake power in the minds of the engineers of the 1880s - by which time the dynamics of loose-coupled mineral trains were well-understood.

 

21 minutes ago, DenysW said:

I note the Garratts started out with brakes on the non-driving wheels (as well) but that these were later removed (once their uphill limits had been empirically established?).

 

I believe this was just part and parcel of a general policy of removing bogie and pony truck brakes as more trouble than they were worth, rather than the result of any more subtle analysis. 

[AlfaZagato]

Citing British Railways Operating History: Volume 1: the Peak District, an unsplit train was tested downhill behind a Garratt on the Ambergate to Pye Bridge.   The Garratt's brakes were found to be gone by Heaton Mersey

[DenysW]

1 hour ago, AlfaZagato said:

Citing British Railways Operating History: Volume 1: the Peak District, an unsplit train was tested downhill behind a Garratt

 

I think this actually shows the importance of the units tasks are quoted in, and the degree to which the engineers understand them at a gut level. Thus the Garratts (or two 4Fs) were expected to develop ~1600 hp to tow trains uphills against rolling resistance. If you assume that 25% of that is rolling resistance* that is against you uphill and helping the brakes downhill, then the locomotive and brakevan brakes have to dissipate up to 590 kW. That is an enormous amount of heat expressed in domestic electric fan heaters (in the UK to 3 kW each) or household gas boilers (say 28 kW each). No wonder the Garratt brakes melted - you just wouldn't expect otherwise provided you had the reference points for what heat means.

 

* From a George Stephenson estimate based on a 1:100 slope

[tythatguy1312]

now that I suspect that virtually every avenue of ideas which could reasonably lead to changes in British locomotives have been explored bar the completely nonsensical, I have 1 idea left. How come American style "simple mallets" didn't catch on in the UK? Ignoring small class sizes, they could've done extremely well on the harsh grades of either the LMS main line or Scottish highlands, particularly on heavy passenger work. Frankly it still scares me that Union Pacific's Challengers were mixed-traffic designs.