Things that seemed a good idea at the time, but in practice are pretty useless.

I recently read in Bradley that Mr. Drummond's F13 4-6-0s (F for fiasco?) had different throw cranks. I suppose that after so many bad ideas, why not add one more.
Pat

 

Here is what the railway author EL Ahrons had to say on the subject in 1925:

"Piston tail rods, after having been tried by Adams for some years on the L&SWR, were discarded on this line about 1896, and were adopted at about the same time by the NER. The reason then given, alike for their adoption and disuse, was exactly the same in each case, namely that the opposite course was productive of wear and scoring of the cylinders. Apparently the question is still sub judice, although the tail rods tend to disappear, partly owing to the increase of the reciprocating masses which they involve."

I suspect that the issue of reciprocating mass was the clinching argument that decided British engineers in the 1920s against continuing with tail rods. They would have become much more conscious of this factor as a result of research during that decade by the "Bridge Stress Committee".

Overseas, tail rods also seemed to fall out of favour in USA and Canada, and at a later date in Soviet Union. France seemed to be 50:50 - some engines had them and some didn't. But in Germany and other Central European countries, tail rods became seen as essential items and were fitted to virtually all steam engines, continuing with them in the preservation era.

 

I suspect that whether a tail rod increases or reduces wear in cylinders depends on how accurately or otherwise everything is aligned. I am dubious about the reciprocating mass argument: surely the mass of a tail rod is very small compared to the masses of the piston, piston rod and connecting rod.

 

Agreed, and as the tail rod is not transmitting piston forces but merely carrying the weight of the piston, it can be made a smaller diameter than the piston rod.

 

I’ve often wondered if the additional costs of making and maintaining an additional gland also came into it.

I suspect in practice the advantages were probably finely balanced and simultaneous developments around that era in better lubrication, more and better piston rings and so on may have been sufficient to swing the supposed advantage one way or another. Perhaps pertinent in the discussion about Adams that as well as piston tail rods, he also preferred single slide bars on his outside cylinder locos - so maybe just had a different conception about how best the weight of the whole piston / rod / cross head should be supported over its length.

Tom

 

Certainly the German engines have a large bush on the front cylinder cover. I assume that this allows adjustment to carry the weight of the tail rod properly, no point in it otherwise.
Pat

 

It was tested on five german BR50 locomotives to omit tailrod.
After 7000 km they measured up to three mm wear and after 70000m they put tailrods on.
BR50 (and52) had single slide bars like Adams and it was stated that this could have been a reason for failure of experiment.
The LNER Tornado pistons has a cast bronce ring carrier on piston and I wonder if that was normal on british pistons without tail rods.
The germans had to be very frugal with bronze or brass due to lack of cupper.

 

Die Badische 18.3 mit sehr deutlich schutzrohr , besonders für die innere zylindern!
https://www.0-gleich-dampflok.de/da...1bc0/ede57655-dad4-35da-f477-6417abac5bcc.jpg

Knut

 

BR Standards originally had a bronze carrier for the piston. I'm not sure whether these were abandoned, or not. No doubt Stdtank can say.

 

Most British lines developed outside cylinder locos after many decades of building inside cylinders locos where there wasn't usually space for tail-rods anyway. Presumably many engineers just didn't see the need to add them when larger locos led to more use of outside cylinders.

 

I'm getting a bit off topic, but could we add round spectacle plates? Why British Victorian designers persisted with tiny round windows when the Americans had much bigger, square ones is anyone's guess...

 

On early American locomotives the steam chests were lubricated with tallow, from a long spouted pot which was kept hot on a shelf over the firedoor. The fireman was required, at the behest of the engineer, to walk out on the running boards and lubricate these steam chests on the move. Whether this was because tallow is a poorer lubricant than the British had, or whether it is because of greater distances between stops I do not know. Locomotive cabs were generally of wooden construction, with large doors on either side at the front to allow said fireman to get out onto the running board. In very hot weather locomotives would run with these doors open for ventilation. Large rectangular doors allowed for large rectangular cab front windows which became the norm from 1840's onward.
The visibility aspect seems largely irrelevant as American engineers, always drove with their head out the side window of the cab come rain, sleet, hail or snow .

 

My understanding was that both the use of tallow for cylinder lubrication and the requirement to lubricate from the running plate whilst on the move were both standard early British practice too

 

In Britain, it was the driver who would sally forth along the running plate to add oil as he felt necessary. The L&YR Atlantics also had full height doors each side of the spectacle plate.

 

Just on the point of large cab windows rather than portholes in Victorian locos - Adams was rather partial to them (look at photos of the Adams radial tank, for instance).

Tom

 

Wasn’t the Ais Gill crash at least partly attributable to the driver spending time on the frames oiling the loco while the fireman struggled with a recalcitrant injector, with the result they were distracted from the view ahead? I seem to recall the loco concerned had better lubrication with no necessity to go round that way, but the driver was somewhat old school and carried it out just because that was what he had always done.

Tom

 

Indeed, that was how it happened.

 

Was pretty standard practice I believe.

When my old man worked inside at Swindon he used to occasionally manage to blag a ride on a locomotive on a running in turn from the works. The only time he ever rode on a King (6008) she was running with a crane to somewhere west of Swindon, running round and then coming back. The run westwards was tender first and apparently the weather was dreadful in torrential rain, the fireman and inspector walked along the running plate and stood on in front of the smokebox on the run to keep dryer, leaving only my old man (who was told not to as he wasn't actually supposed to be there) and the driver to get wet on the footplate.

Apparently the run back chimney first was very lively as the driver basically pushed the regulator up to the cab roof and she took off like a scalded cat.

 

My thoughts are that it was probably originally simpler to mount circular rather than square cornered glass in a vibrating iron spectacle plate without risk of it shattering. Windows in American wooden cabs were more akin to carriage windows.

 

On the GWR around the turn of the century, some 4-4-0's, and possibly other types, had doors in the front cab sheet to allow access to the running plate. Somewhere I have a great MIC book written by a GWR engineman in the 1890's, which describes how to attend to a crosshead running hot whilst the engine is still running. Mind you, other 'advice' includes running the engine 'sharply into some trucks' to reseat a blowing clack, and using the fire irons to ram a bolt into the crown if you drop a plug. It's probably just as well that some things moved on...