BR Standard class 6 No. 72010 'Hengist' and Clan Discussion Thread

Cheers. Seems relevant in context, so I'll ask if there's any idea whether any on that list have been cleared for use on the big railway?

 

Not much call for these locos on the big railway, the standard 4 Tender locos tend to get the whitby turns at NYMR...

 

Fair enough, though even in recent years, there have been plenty of exceptions to express locos with 10-12 and a thunderbird on, right down to a 2MT and pair of 57xx panniers.

I was just wondering aloud whether such a mod would kybosh "grandfather rights" and mean jumping through hoops to gain mainline certification.

 

No.

 

Thats the rub, one hopes that by being able to demonstrate that a substitute component behaves in an altogether similar or even preferable way than what it replaces is enough , but as Ian has stated if those properties are different and the behaviour of the bogie assembly in relation to the loco as a vehicle is changed as a result , then a simulation of how those changes could manifest may well be necessary, followed at a later date by wired up test runs to qualify the simulation. Even if the entire design of the bogie were changed to that of say a Royal Scott , Then sure the bogie design would be passed off but some demonstration that the new component behaved as it should on a Clan would be required, again wired up test runs, computer sims etc

 

To what extent do "grandfather rights" exist for a class of loco that was extinct before the end of BR steam?

 

As I understand it, the 'Grandfather Rights' exist because the loco, component or system had proven itself in everyday service on the main line so could be expected to be adequate today. I'm not aware of any time limit on this; it might have been proven up to 1968 or up to 1958, but the point had been proven.

 

The End of BR steam was a few Black 5's and a Brit. ?

 

My understanding, informed by the conversations I'm having as part of 35011 GSNLRS, is grandfather rights as a concept only really applies to loco classes that never disappeared, and doesn't really apply anymore at all, certainly not to classes of locomotives that were scrapped entirely, as the locomotives haven't operated on the mainline since 1968 (or earlier). 72010, 60163, 2007 etc. will have to demonstrate the full safety case for their locomotive as if it were a completely new machine (like the 5AT). That said, being able to say "these parts are the same as X and we're operating them in the same way" should help ease the burden, but if you're using the same part in a different way, that's a problem. For 35011 I can demonstrate that most of the locomotive is the same as either 35028 of 34067 for example, though our new middle cylinder may need more justification to demonstrate it's suitability. If you're inserting a completely new design for a part, one will have to demonstrate how it impacts on the overall "risk" of the locomotive, and how that risk is mitigated. For 35011 this means that I have to demonstrate that our new crank axle material is suitable and doesn't bring in an increased failure risk compared to the "original" design. (Apologies for minor thread drift to 35011, I'm trying to give concrete examples of how the process works)

 

Indeed it is fortuitous that for the test runs on 60163 on the GCR, 70013 - a bona-fide 'grandfather' was used as a comparison and so a set of data for a vehicle not quite identical to a Clan already exists. One wonders whether the coil sprung trailing truck on 72010 ( As 71000 , not as 70013), as well as the bogie may require some qualification...

 

srapley has taken this further than I since I was commenting merely on the time as specified by MellishR: extinct before the end of steam and that this wasn't a criterion. 2968 went main line in 1996 based on, among other things, Grandfather Rights. She had been withdrawn in December 1966 and the class became extinct in February 1967, eighteen months before the end of steam. From an engineering standpoint, much more is involved in terms of design, materials, tolerances, inspection, maintenance, etc. Replacement parts must be 100% as original in all respects to qualify or must pass scrutiny.

 

The point I didn't mention, but doesn't apply to 72010, is grandfather rights does apply (sort of) to individual locomotives that have maintained a mainline presence as it were, like 35028. Either way, I look forward to the day both 72010 & 35011 are out on the mainline!

 

The pony truck arrangement drawing for 71000 shows that the same truck would have been used for the Lot 242 Clans.

 

Genuinely not seeking to be awkward here, but weren't there substantial changes to elements of the chassis design applicable to all three classes of Standard 'pacifics'? Presumably certain modifications 'on the list' were approved, even if not fully implemented, so at what stage could a (legacy) drawing or component be considered "approved"?

 

I think that is a question for ianh1 to answer. Certainly, there was a later frame arrangement drawing for the Lot 242 Clans.
The Hengist team found that there was a major modification done to the intermediate drawgear on the Britannia Class as late as 1959. The drawings were done by Swindon Drawings Office. The drawings are not listed in the Britannia Class official drawings lists, the mod was that late. Not all the of the Class were modified, but 70000 and 70013 were, so there is a reference for the modification. These are interesting times.

 

I'll try and answer your questions!

In our initial discussions with our Assessment body, we were told that we needed to demonstrate how the design of 72010 had been established. Our starting point was the Lot 221 drawing list for the original Clans which is at the NRM. We have photographed this. It shows the drawing list for the locomotives and also shows drawings that superseded earlier drawings at renewals. For example, the steam collection system within the boiler went through 3 developments and all of these are shown in the Lot 221 drawing list. Unfortunately there isn't a Drawing list for Lot 242. However we have most of the Lot 242 drawings. Some were brand new drawings - like SL/DE/22085 which is the Lot 242 Frame Arrangement and is unique to Lot 242. Other drawings show that the drawing was applicable to Lot 242 and Lot 221. Sometimes you can see that it was applicable but someone rubbed out the Lot 242 applicability. So we have a high level of confidence in identifying the Lot 242 changes.

All of this has gone into a spreadsheet showing the base design (i.e. Lot 221) and the changes for Lot 242. We have then added another column showing the changes for 72010. For example, 72010 has fitted bolts instead of cold formed rivets. So we can demonstrate to the Assessment Body have the design has come about. If we can demonstrate that a component has operated safely on the railway in the past and present, it helps get that component approved. For example, 70000 and 70013 are running on the main line with exactly the same bogie design as 72010; 71000 is only slightly different in that the side control spring is a different rating.

Whereas the Lot 221 Class 6 had the same frame arrangement as Class 7 Britannias, Lot 242 shares the main components of its frames with 71000. Class 7 suffered from frame cracking (see Bill Harvey - 60 Years in Steam). A mod to address this was made to the original Class 6 and Class 7 to bring in a "Combined Spring Bracket and Hornkeep Fixing" (SL/DE/21130 - the date is obscured on the drawing) which is a single leg spring hanger. This evolved into the 4 leg combined spring bracket and frame stretcher that you can see on 71000 and 72010.

Yes 72010 shares the same coil sprung pony truck (with cast radial arm) with 71000. The ride is reported to be much better and the fabricated arm on the original design suffered from cracking around the pivot. The Locomotive Standards Sub Committee Meeting Minutes (May 1953) tell us that the coil sprung version was intended for the last batch of 10 Class 7 engines but this didn't happen.

Problems with Fore and Aft motion run throughout the minutes of the LSSC meetings and it predecessor. The problem reached a head in 1958 when 70028 was in Swindon getting a new dragbox to a new design. Scotland reported problems with bent drawbar pins and on the Midland division of the LMR, 70044 had a "seriously distorted" dragbox. Swindon developed a new design changing from a solid drawbar (retained by vertical pins on engine and tender) to a new dragbox where a drawbar spring (a series of plates with rubber rings on both sides) was on the engine. This change was recommended for Class 6 and Class 7 but it was left up to the regions to implement. As std tank says, this arrangement is definitely fitted to 70000 and 70013.

The LSSC meeting minutes are proving to be a valuable source of information. They discuss the problems that arose in service and how those problems were addressed - including some of the blind alleys that they had gone down.

 

Must say I'm impressed greatly, with your research..very impressed...

 

When you don't do the research you get into difficulties, like manufacturing parts only to find they were superseded in later years. But it is inevitable since you cannot read all the paperwork before you even start, so I think the team are doing a brilliant job with all this detail checking. Must bode well for the final examination surely?

 

I totally agree..but also, I have always tried to employ lateral thinking. Surprising what it brings up sometimes....

 

Hot off the press - literally. Today we're at CTL Seal for day 2 of riveting the front buffer beam. Here the outside platform support plate angles are being riveted to the buffer beam by Varley Boilers