Was the 'WOLF' the most powerful passenger steam loco in Britain

[Combe Martin]

The Gresley P2s were the most powerful passenger steam locos in Britain, but 2006 'Wolf of Badenoch' had a wider fire box than the other 5, so was it the most powerful of them all ? 

[AndrueC]

11 minutes ago, Combe Martin said:

The Gresley P2s were the most powerful passenger steam locos in Britain, but 2006 'Wolf of Badenoch' had a wider fire box than the other 5, so was it the most powerful of them all ? 

https://www.therailwayhub.co.uk/10522/lms-coronation-class-britains-most-powerful-locomotives/#:~:text=3300hp under test,for the British railway network.

 

And according to Wikipedia:

 

"No. 6220 Coronation held the British steam speed record between 1937 and 1938, 114 miles per hour (183 km/h).[2][3] It held that record until beaten by 4468 Mallard in 1938. Secondly, No. 6234 Duchess of Abercorn holds the record to this day for the greatest British power output to be officially recorded on an attached dynamometer car, achieved in 1939."

[Combe Martin]

Yes, but I wasn't asking about outright speed (the P2s had smaller driving wheels so were unlikely to have been the fastest) but rather theoretically, did having the wider firebox give it a theoretical higher tractive effort than the other 5 ?.

[LMS2968]

4 minutes ago, Combe Martin said:

Yes, but I wasn't asking about outright speed (the P2s had smaller driving wheels so were unlikely to have been the fastest) but rather theoretically, did having the wider firebox give it a theoretical higher tractive effort than the other 5 ?.

No. Firebox size isn't part of the Nominal Tractive Effort calculation*, and Nominal Tractive Effort is not a measure of power output. Power is the actual tractive effort being developed at the time multiplied by the speed at which it was generated. Nominal Tractive Effort, if it has anything more than a theoretical value, applies only at zero miles per hour, so, say, 40,000lb of tractive effort multiplied by zero mph gives a power output of 0 horse power.

 

*bore squared x stroke x number of cylinders x 85% of boiler pressure divided by 2 x driving wheel diameter

 

[Combe Martin]

I've often seen it quoted that the P2s were the most powerful British passenger locos, so is that wrong ?, or is it a case of "we'll never know" because a dynometer test wasn't done.  Will we have to wait until 2007 is on the rails ? 

[Bon Accord]

Wouldn't the larger firebox and it's ability to generate more heat/make steam/evaporation rates only really mean that it'd be better able to sustain higher power outputs for longer than other locomotives rather than specifically having a higher maximum power output?

[Wickham Green too]

A wider firebox will be heavier so will should increase the power that can be transferred to the rails - but not by much.

[LMS2968]

6 minutes ago, Combe Martin said:

I've often seen it quoted that the P2s were the most powerful British passenger locos, so is that wrong ?

Yes it is wrong. You cannot calculate the power output; you have to measure it, either at the cylinders (Indicated Horse Power) or at the leading coach (Drawbar Horse Power). The readings will be different as some of the i.h.p. is absorbed moving the loco. I doubt very much if 2007 would ever be subjected to a test requiring the generation of over 3,300 i.h.p., and if it were to be it wouldn't be coupled to the equipment necessary to measure it.

[MartinRS]

With the usual caveats about the accuracy of Wikipedia here is the data from the information boxes for each locomotive class

 

• Wolf of Badenoch LNER Class P2                           Tractive effort    43,462 lbf (193.33 kN) at 85% boiler pressure
• Duchess of Abercorn LMS Coronation Class        Tractive effort    40,000 lbf (180 kN)

Without practical test data for Wolf of Badenoch we'll never know.

 

And just remember in theory there is no difference between theory and practice, while in practice there is.

[LMS2968]

14 minutes ago, MartinRS said:

With the usual caveats about the accuracy of Wikipedia here is the data from the information boxes for each locomotive class

 

• Wolf of Badenoch LNER Class P2                           Tractive effort    43,462 lbf (193.33 kN) at 85% boiler pressure
• Duchess of Abercorn LMS Coronation Class        Tractive effort    40,000 lbf (180 kN)

Without practical test data for Wolf of Badenoch we'll never know.

 

And just remember in theory there is no difference between theory and practice, while in practice there is.

And the Nominal T.E. for U1 69999 was 72,940lbs. Totally meaningless.

[Bucoops]

The GWR lot can't claim Truro did 100 as it wasn't measured, us LNER lot can't claim a P2 was the most powerful for the same reason.

[Combe Martin]

So the claim that the P2s were the most powerful is just based upon the Nominal Tractive Effort, not any actual test.  And I was just referring to passenger locos.

 

Maybe we'll have to wind up the owners of 2007 to really test it then!  I presume they'll have to borrow the dynometer car from Shildon and get it into working order ! 

[jjb1970]

Are we talking about power or tractive effort? Two different parameters. Power is the rate of doing work, while mechanical work is a function of force and distance it is not a function of time as for power. Shunters can have very high tractive effort from small engines of modest power.

[Tumut]

Hello All, if the new P2, 2-8-2 Prince of Wales is tested for power output on Network Rail, would not a contemporary test car be available, and where could it be comprehensively tested, and at what cost ? Regards, Tumut.

[Michael Hodgson]

32 minutes ago, Tumut said:

Hello All, if the new P2, 2-8-2 Prince of Wales is tested for power output on Network Rail, would not a contemporary test car be available, and where could it be comprehensively tested, and at what cost ? Regards, Tumut.

The NER dynamometer car is part of the NRM collection ... and I suppose a good place to test would be going down Stoke Bank.

 

Try making a safety case for thrashing an unproven engine with veteran measuring equipment on a modern high speed line !

[Wickham Green too]

Right ......... let's start with a safety case for the wooden-centred testing wheel - no certification authority alive today will ever have see anything like that on the rails !

[Tumut]

Hello there, someone else on this site wondered about the longevity of existing preserved steam on the mainline bearing in mind that the newest xBR steam, 92220 Evening Star,completed in 1960, is now 64 years old, Bullied Pacifics are at least 73 years old, Clean Castle is 74 years old, so at which point will a future safety review decide that age , of itself, will stop Network Rail access, and will steam be able to comply with future safe working regimes ? Even secondary main lines, such as the Settle and Carlisle, or Central Wales, or Scottish Highlands, will all, at some point, be resignalled in some form or other. With the modern trend of all semiconductor control, complete with its relatively short lifespan compared to mechanical signalling equipment, even the safety case for heritage railways may become more difficult, and expensive, despite the generally excellent safety record of low speed heritage railways .Regards to all, Tumut.

[Miss Prism]

3 hours ago, Bucoops said:

The GWR lot can't claim Truro did 100 as it wasn't measured

 

The speed was inferred from the 1/4-milepost timings. Which is how speed was measured in those days!

 

[Cwmtwrch]

With 6ft 2in driving wheels it is open to question whether the P2 shoud be classed as a passenger or a mixed traffic engine. Stanier  Black fives had 6ft drivers, as did GWR Halls, while the Princess Coronation class had 6ft 9in and Kings 6ft 6in [deliberately reduced from the Castles' 6ft 8½in]. Bullied pacifics had 6ft 2in, and GWR Counties had 6ft 3in, and all three were classified as mixed traffic locos.

[pete_mcfarlane]

4 hours ago, Combe Martin said:

I've often seen it quoted that the P2s were the most powerful British passenger locos, so is that wrong ?, or is it a case of "we'll never know" because a dynometer test wasn't done.  Will we have to wait until 2007 is on the rails ? 

I thought one of the P2s was sent to the French loco testing station at Vitry? That should have generated a load of data on them. 

[KeithMacdonald]

Some might say that "the most powerful passenger steam loco in Britain" was a class that never actually operated in Britain. Built in Manchester by Beyer, Peacock & Company for the New South Wales Government Railways in Australia. But perhaps they did test a prototype on British rails before shippinng them to Oz?

 

Quote

 

The New South Wales AD60 class were Beyer-Garratt patent articulated four-cylinder, simple, non-condensing, coal-fired superheated, 4-8-4+4-8-4 heavy goods steam locomotives ... Tractive effort 59,560 lbf (264.9 kN), later 63,490 lbf (282.4 kN)

 

 

https://en.wikipedia.org/wiki/New_South_Wales_AD60_class_locomotive

[PatB]

Given the British aversion to mechanical stokers, ultimate power is a bit academic, as sustained power output is limited by what one (or maybe two, given the room) man can shovel for any length of time.

[kevinlms]

7 hours ago, Cwmtwrch said:

With 6ft 2in driving wheels it is open to question whether the P2 shoud be classed as a passenger or a mixed traffic engine. Stanier  Black fives had 6ft drivers, as did GWR Halls, while the Princess Coronation class had 6ft 9in and Kings 6ft 6in [deliberately reduced from the Castles' 6ft 8½in]. Bullied pacifics had 6ft 2in, and GWR Counties had 6ft 3in, and all three were classified as mixed traffic locos.

And of course the Bulleid Pacific's wouldn't have been built during WW2, if they weren't considered as 'Mixed Traffic' locomotives!

[Combe Martin]

Surely the P2s were only ever designed to be passenger locos, and the reason for the 6ft 2in drivers was the difficult 'road' they were designed to operate on.  Was there space in the frames for an 8 coupled 6ft 6in wheel set ?

 

Has anyone ever seen a photo of a P2 on a non passenger working ?  

[rogerzilla]

10 hours ago, pete_mcfarlane said:

I thought one of the P2s was sent to the French loco testing station at Vitry? That should have generated a load of data on them. 

Bulleid had an absolute nightmare with 2001, mainly hot bearings, and they didn't get any meaningful results.