Bulleid Pacifics - Past or Present

When Wadebridge was making some rather syncopated beats a few years ago I seem to recall the culprit was wear in the 3:8 rocking lever pivots, which were accessed by taking up the (concrete) smokebox floor. Not a five minute job to put right. Running longer cutoffs will tend to mask some of this, I suspect; more travel makes the slack less significant, but after a point they just need reconditioning.

 

I believe one issue that the originals suffered from was that the combination levers were prone to bending - probably not surprising given the lightweight nature of the various rods, it's possible the weight saving went a bit far. A distorted combination lever would throw the timing of one cylinder out.

Tom

 

What's this I spy moving slowly but steadily northwards on the A1(M) this evening near Stevenage as I drove home? Why, it's 257 Squadron!!

Where's that off to, then?

 

I think it's a guest at the Mid Norfolk Railway's Steam Gala this weekend.

 

Yes, it is currently shown as a guest for that event. Then it's due back to its Spa Valley homebase (my local heritage line) briefly for the July summer Steam Gala before heading off to the Mid Hants for a while - I think so anyway! And I shall be hoping it will be in action on the Mid Hants on 13 August, so I can go and have a run behind it plus some photos, to mark 60 years to the day when I had my only run behind it in normal steam days!

Bryan B

 

There is a nice overview of the Strictly Bulleid 2 event on the Southern Locomotives Ltd website. A real triumph for the SLL with four of its Bulleid pacific locomotives working there.

 

https://www.southern-locomotives.co.uk/News/news.html

 

Some nice features on Strictly Bullied II in the new issues of both Trackside and Heritage Railway magazines.

 

Some time ago I seem to remember an article on suggested/proposed names and numbers for the next batch of 'Merchant Navy' locomotives.
Can anybody on here help with what that list was? I believe one name on the list was 'Yeoward Line'. Thanks.

 

I’ve not read about any proposal for further MNs and given their restricted route availability what would be the need? If they were built there were many possibilities, Straight Line, Wavy Line, Washing Line, Border Line, the list is endless!!

 

Don't forget Grey Funnel Line
Pat

 

It could have fought off the western region destruction of the Waterloo-West of England line for a few more years, at least as far as Exeter!

Bryan B

 

With modern stress analysis and what the chips are now capable of in home computers would it be possible to redesign the combination lever?

Either by improving the exact shape or the metallurgy. Knowing how to improve inspection might be worth while.

How the Bulleid Pacifics which were never rebuilt eventually settled down to go ever so much more reliably, under BR and certainly in preservation wether being worked hard on the main line or not, is a study in itself . However memorable the failure of the valve gear under Tangmere denting the oil bath round it is there are a litany of failure points that are ever so much better now: stretched chains driving the valve gear, steam reversers not staying put, oil bath leaks and fires in the lagging round the boiler, short lives of the main inner firebox, buckled coupling rods after slipping, none of them known now like they were.

 

While some of that might be better maintenance etc, there is also a very large component of a numbers game. Back in the day you had 140 locos probably running an average of 30-40,000 miles per year each. Now you have only one operational mainline original condition loco, and a handful on heritage lines; and most of those are probably running around 5,000 miles each per year, and at lower speeds. So even if the per-mile failure rate were no better today than 70 years ago, you'd expect to hardly ever see a failure now of the type that would have been frequent occurrences back then.

On the steam reversers specifically: there were many modifications done at the time that made them more reliable. But I think the major one was a change in position between the original Merchant Navy locos and later ones (and Light Pacifics), which made access for inspection easier. A steam reverser is a very good device, but the one thing you absolutely have to be on top of is making sure the cataract cylinder doesn't leak, and keeping it topped up if it does. That requires regular inspection, and the access to the reverser on the original locos was poor. My strong suspicion is that the lack of access meant that regular inspection was routinely skipped, with the result that the reverser drift issues developed as the cataract cylinder leaked. Moving it to a less congested location promoted better access and better performance.

Tom

 

I can't see any documented evidence (after a quick look) from the time that more Merchant Navy pacifics were planned and any such naming proposals with names, may just have been speculative.

The third batch 35021-35030 were delivered post-war and as such suffered supply issues and 35030 wasn't delivered until April 1949 (order having been placed in 1947) which came close to when Oliver Bulleid was gone from the SR. The decision to rebuild the class from original form could have concluded as an alternative to scrap and build more Standard classes as Britannias had performed well during the class stand-down following the Bibby Line incident in 1953. Projections made at the time were that MNs would become end-of-life in 1975 although this may have been an accounting ploy. (ref Derry 2001)

I therefore can't see a decision being taken to build more MNs in rebuilt form after OVSB had gone from the SR?

 

The Latest News page of the SLL website has been updated today, with news of all our fleet. https://www.southern-locomotives.co.uk/News/news.html

 

Wasn't this posted on July 6th Nick?

 

A report on Strictly Bulleid II was added to the website News page then, and you probably saw an update sent to SLL shareholders.

 

Unless 34007 is different to other West Country class locos; the rocker shaft bearings are not accessed from the smokebox floor, but via a vertical inspection panel below the smokebox floor.
That is only for the outside valves, the rocker shaft for the middle valve, is accessed by a removable plate on the left hand main frame, just above the left hand crosshead.

 

34053 Sir Keith Park will be renamed 303 Squadron (for one year) on Sunday 1st September at the Spa Valley Railway. Richard Green (locos -in-profile) has created two new print for the event.
There are more details here: https://www.southern-locomotives.co.uk/News/news.html