Ton up Tornado

As a student of English - fair comment. Edited...

 

Er - bit extreme?

Worth reading Peter Townend's "East Coast Pacifics" book. The work done on the A1s to remediate the poor running of some members of the class is well documented. 60136 Alcazar was mentioned specifically as one such perpetrator.

It is interesting to note that the development of the A1s - arguably starting with the P2s - had through the Thompson A2 Pacific designs and the Peppercorn A2s, a number of handling issues. The Thompson A2/2s initially rode well but quickly became more rough riding as they got closer to shopping.

I'm yet to find a direct quote on the A2/1s being so bad - one wonders if the overall longer wheelbase and higher tractive effort had something to do with it.

Nevertheless it's a habit of riding that started with the A2/2s, went through the A2/3s and came out the other side with the A1s. No quick fixes for it either. I wonder how bad riding the 90,000 mile per shopping A1s must have been?

 

Nothing from Joe Duddington about it...

 

What an amusing amount of froth is being generated by folk who have never been on an A1 footplate at speed! Yes, the class is/was prone to a degree of lateral sway at certain speeds but Peter Townend commented that Tornado was no worse than the originals and well within acceptable limits. Geoff Bird, who rode on Saint Mungo's footplate at a recorded 103mph, noted that there was a resonant speed at about 75mph when the locomotive exhibited a degree of sway, above which everything stabilised and "became astonishingly smooth, like gliding on ice". The fact that Dave Proctor was happy firing at 100mph suggests all was well during this trial.

Foxy

 

Having now seen the BBC Documentary a couple a of times, and after reading the discussion here are my observations.
The Tender did seem to sway a bit at times, but as the Camera does not show the Speedo we cannot have any accurate idea of how fast it is moving at that precise point and may have been moving at much less than 100Mph. It could have also been travelling over points, rough track, etc. as the outside can not be seen no one can tell.
While the closing credits are running there is a scene taken from a camera mounted on the front of the Tender, the Speedo at this stage is showing at or close to 100 Mph there seems to be very little movement of Engine or tender at this stage and would myself consider this to be remarkably stable given the speed the loco is travelling at (been on much rougher locomotives at half that speed) and that both engine and tender are 'rigid frame'/'fixed wheelbase' vehicles, the Fireman can also been shovelling during this footage so I don't think (personally) instability is going to pose any problems.
Mention is made about keeping the tender as full as possible to avoid skidding Wheels which brings to mind a couple of questions,
Down under we have a couple of Classes of Locomotive which have Hydrostatic Tender Brakes, where Brake Cylinder Pressure is reduced as the tender is emptied of water. Does any loco in the UK have anything similar?
Secondly does Tornado's Tender have Compensated or Uncompensated Brake Rigging?

 

There speaks (writes) a scientist.

 

I hope I'm not included in that froth! Only adding to the background of the class' history.

 

British steam loco`s are not fitted with VARIABLE LOAD CONTROL VALVE short for VLCV only fitted to freight wagons and underground trains dare say modern EMU`S as well. PS more froth LOL . FISH7373 81C NFP

 

No Simon, of course not!

Foxy.

 

Vertical Load Control Valves maybe?
Kind regards
Jos Koopmans

 

I don't think that is what NSWGR 3827 was referring to. I don't believe 60163 has compensated brake rigging as I think it is like other LNER 8 wh tenders with two pull rods (one on each side) and no compensation between brake shoes. I'm told that is the reason why the original tender brake gear had to be replaced but I'm quite happy to be told I'm talking rubbish.

 

Thanks Foxy - sorry a bit gruff from me earlier, it's been a long week.

 

Variable Load Control
Although the retardation controller is a form of load control - because the braking rate is monitored, a heavier train will require more brake cylinder pressure, so the retarder will not reach its setting until the right rate is reached - it is rather crude. It only monitors the whole train, not individual cars. This means that lightly loaded cars in a generally heavy train are still at risk from a skid or wheelslide, as it is called. The solution is in variable load control. The car weight is monitored, usually by a lever fitted between the car and the bogie, which detects the bogie spring depression as weight increases. The lever is connected to a regulating valve in the brake cylinder feed pipe, so that the brake cylinder pressure is varied in relation to the weight of the car. With the introduction of air suspension, load control is achieved by monitoring the level of air in the suspension system and regulating brake cylinder pressure accordingly. Nowadays, the same load signals are used to vary acceleration and dynamic braking according to car weight.

 

So in essence it's the same principle that my old Renault 16 had: where a lever connected to the rear torsion bars adjusted a valve that controlled the admission of fluid to the rear brake cylinders to stop the rear wheels from locking up when the car was lightly loaded.

 

The theory sounds right. The landcruiser ute that I drive for work can (in theory) take up to 1oookg in the tray so it has a similar device to adjust braking with differing loads. It was not adjusted correctly for a time and it had terrible stopping power.

 

Not good with a tonne in the tray!

I think it was actually pioneered by Citroen in the DS in 1955; but when the 16 came to market in the UK in 1966 it was the only conventionally-sprung car to have it AFAIK.

 

Am unable to provide a diagram or link, However The device I am referring to (What we have on Loco tenders down under) is part of the Westinghouse A6-ET Brake equipment and is commonly called the 'Hydrostatic tender Brake' and has been fitted to some Locomotives since c.1943. It contains 2 Valves, a H Control Valve & a F Relay Valve. The H control Valve takes Air from the Brake Cylinder on the Loco & water from the tender, the more water in the tender the more air is fed to the F relay which in turn provides Main Res Air to the Brake Cylinders on the Tender.
Compensation between Brake Shoes/Blocks is the question I was asking and The reason I ask about is that in my experience Locomotives with uncompensated Rigging tend to be more prone to skidding Wheels.

 

There is a documentary about Tornado on BBC4 on 7/8/17 at 21:00 - is this new material?

http://www.radiotimes.com/tv-programme/e/fprc54/tornado-the-100mph-steam-engine/

 

99% sure that's a repeat of Tom Ingall's excellent programme.