Preserved 9Fs

Annoyed!! I have just completed a list of the various Standard tenders, complete with notes, which took some time. When I pressed the post button it would not accept it. What is going on Mods?

 

Thanks for that class8mikado, that link explains it well, and looking at pictures of 92212 and 92240 I can see the difference now.
Many thanks,
Daniel

 

I believe one difference between similar tender types (the "A" suffix?) is the layout of the cab doors/rear hand rail. One had the doors/handrail on the loco, on the other it was on the the tender. The Brits had both arrangements I understand.

 

Has the fesability of having flanged centre driving wheels for 9fs ever been considered? This would overcome the checkrail issue but may increase the minimum curve that could be negotiated.

 

Using a very scientific method (Comparing in a computer game). It's apparent that the 9F fixed wheelbase is pretty much the same length as that of a class 40 and 45 bogies, Though as to whether the bogies allow sideways movement that is perhaps not possible with a 9F is another matter as well as they don't have wheels exactly in the middle of the wheelbase, so presumably not the best comparison.

 

The Class 40/45 bogies weren't rigid wheelbase, though. Effectively a 2-6-0 to use the Whyte notation.

 

The middle wheels aren't just flangeless; they're wider across the tyre as well, to allow the locomotive to traverse tight curves. I can't help but feel that if it had been possible, all wheels would have been flanged from the beginning.

Mark

 

For most BR std locos including 9fs the quoted: 'minimum radius curve without gauge widening 6 chains (4 1/2 chains dead slow)' in 'British Railways Standard Steam Locomotives' by E S Cox. So the flangeless wheels together with thinner flanges on second and fourth axles allowed the same access as other classes.
In the 1950s steam locomotives were still being built, also numerous goods yards, loco depots and other facilities existed which had to be accessed. These are far fewer now and many have been rationalised in track layout. Even including the Heritage lines it is still far fewer than back then.
So my original question (post 64) still stands, it may not need to negotiate as tight radius curves, or modern design and build may achieve the result in a different way.
Apparently the flangeless wheels could drop off the track in the aformentioned yards, something which dosen't happen with model locos!

 

As I said, if possible it would have been done, but thanks very much for putting the 'meat on the bones' there . The bigger problem, even if you were to put flanges on your middle drivers, is that now you introduce a further possible variable - that tight radii trackwork couldn't be traversed, so you would have to have a complete assessment of available routings for the locomotive. Now, as the 'powers that be' wouldn't do a similar exercise for raised checkrail crossings, (which to me would have been a very simple exercise), preferring instead to simply impose a 'blanket ban' on flangeless wheelsets, what chance is there? It's bad enough with clearance restrictions for some classes, be it either height (despite locomotives conforming to 'Group Standards') or width (such as some GWR classes), or 'throw' at crossings or curved platforms.

Sadly, I fear that we will not see a 9F gracing the 'big railway' again, although I'd love to see it. I'll just savour my runs behind 92220 in 1976

Mark

 

One wonders if the rules of open access would allow you to bring a case for a 9F running on the mainline and force NR into making an assessment rather thank BRs blanket no!

 

Interesting thought. However, who has to pay for any investigations?

Also, this is where Group Standards comes into play, & whilst getting a derogation for not having, inter alia, air-conditioned cabs and yellow ends on steam locomotives is a reasonably straightforward and (whisper it quietly) common sense thing, the same cannot be said for flangeless wheels, particularly in this risk-averse world, and therein lies the crux of the matter.

Mark

 

I can tell you that 92207 has seen quite a lot of progress and can be seen at Welcome To Somerset & Dorset Steam | Somerset and Dorset Steam along with two other steam locomotives being restored

 

Black Prince at the NNR last year.

 

I wonder what might happen if a 9F gained an additional flanged wheelset? IIRC, and I might not, the flangeless wheelset was incorporated to allow the type around very small curves, say 4-5 chains, provided it was driven very slowly. Now it is not beyond probabilities that the modern network doesn't include such curves anymore and there might not have many of them originally anyway. Does anybody have the maths to calculate the minimum curve radius of a 9F if all wheels were flanged ( I used to but I most certainly can't remember how to now!)?

Regards

 

Something we were casually wondering yesterday. For those lines who have a 9F, they are generally too large for the traffic on offer, so normally they are worked at well below their theoretical capacity.

Given that, would there be an advantage in adjusting the safety valves so that they blew off at maybe 225psi, or even maybe 200psi? You'd still have a loco capable of shifting pretty much anything most preserved lines could throw at it, but with reduced strain on the boiler (and reduced water-side temperature of the inner box) you should get an increase in boiler life shouldn't you, particularly for the firebox?

The same might apply to other very big locos used on preserved lines with 250psi boilers - for example Bulleids. It's rare you see one with the steam chest pressure much above 175psi anyway, so why not "detune" them a bit and increase the fatigue life of the firebox?

Obviously, there is a very minor theoretical decrease in thermal efficiency, but in practical terms, thermal efficiency on preserved railways is rubbish anyway - too much stopping and starting to allow big locos to be driven optimally. So a tiny increase in coal consumption would, I'd have thought, be well and truly outweighed by increased boiler reliability.

Tom

 

The curves in question are unlikely to be "In the open" but more likely to be within depot areas with restricted clearances, structures and other lines all denying any opportunity to ease the radius significantly.
On the NYMR we did have one curve of less than 4 1/2 chain at Newbridge that has needed attention, this was on the pit road and required the demolition of 6 metres of the pit so that the curve could start earlier.
We still need to locate another suitable crossing nose to reinstate an adjacent siding.

 

With the play built in its going to be in the same league as a P2 with rollerbearings ! or the 47XX

 

2-8-2? Didn't mention a 2-8-2

 

Sorry, wrong fella , was a pit tiddly popped last night

 

Just seen a picture of 92214- mightily impressive getting it back into one piece as quickly as they have- not sure its new livery will be popular with the purists however.....Looks really smart!