What were the 4s for?

Thinking about all the power classifications of steam locos; were the 4F and 4MTs designed with particular types of train haulage in mind?
Panniers, USA tanks and Jinties were all 3F tank locos and were capable of trip working. The Midland had a 3F tender design as well for longer journeys.
Moving up the scale there were Halls, Black 5s and B1s with their 5MT classification for heavier duties.
This prompts my question; which duties were the 4Fs and 4MTs intended for?

The GWR had several classes of 2-6-2T which were 4MT, the Southern had the U & U1s which were 4P3F, the LMS had several classes of both F and MT whilst the LNER had their 4MT B2 class. After nationalisation BR gave us 4MT tank and tender classes. Did they haul heavier trains on routes requiring a lighter loco perhaps?

 

The classifications P, F and MT were BR classifications, the system originating on The Midland Railway, then the LMS, and they were foisted on to the other regions after nationalisation. The designation 4F, for example, was unknown on the GWR, LNER or Southern. Neither the Midland or LMS used the MT classification; the LMS would use, for instance, 5P5F for the Black Five.

P = passenger; F = freight and MT = mixed traffic, although the boundaries were blurred. The Ivatt Class 2s came as tender and tank versions, but were otherwise identical, yet the tender locos were 2F and the tank engines 2P. The 4Fs were designed as freight locos but did quite a lot of passenger work, sometime up to secondary expresses.

Don't believe everything you read on the cabside!

 

Fast suburban work immediately comes to mind, 61xx's on Paddington - Reading and Stanier/Standard tanks on the Tilbury & Southend, A Pannier or Jinty might shift the same loads, but be far too slow for such work, plus a smaller range.

Course in the case of Manors, Standard 4's of both tender and tank variety, they quite often turned up where extra power was needed but larger class 5's were barred, the Cambrian being the obvious example.

 

The 57XX and all members of this class were classified 4F by BR as were the 15XX & 94XX pannier tanks

 

I thi k what the OP is asking, is why did they build an intermediate loco between class 3 and 5. David1984 has largely answered this, although it's far too complicated a question to simply and fully answer.

 

The Midland was a 'small engine' railway: its Chief Civil Engineer imposed strict limits on engine weight and size due to bridge restrictions (which needed strengthening; and tight curvature, requiring short wheelbases. Whether or not the restrictions were fully justified is another question, but they existed and loco types an designs had to conform. On the passenger side, the Midland believed in short but frequent trains so a relatively small loco was capable of working all its traffic, hence the Compounds. Goods trains, though, were heavy, but the weight and size restriction limited the Railway to nothing bigger than the 4F, which required assistance on the heavier workings.

The real answer was what we would now call 'infrastructure improvements', i.e. bridge strengthening and track realignment - both expensive operations in capital cost. Instead, the Midland used double heading as more-or-less its standard operating method, also expensive but the expense was spread out and didn't arrive in one lump, as the necessary improvements would entail.

Other railways, of course, did have larger locos, both for passenger and goods traffic, but not all their trains would require a big engine. Something smaller and useable over secondary routes where the big engines were barred was also needed.

 

It all depends on the railway. The LNER had little use for '4's . It inherited some, of course, but it didn't build many.

 

If even the GWR bought some ex ROD 2-8-0's why did the Midland/LMS not buy lots of them ?

 

What for? They did buy some, but they weren't exactly popular with anyone and didn't last long. Partly there were loading gauge problems, but they were very different to anything else on the LMS. Later they did buy several, immediately scrapped the engines but attached the tenders to ex-LNWR locos. There were fewer LNWR tenders than locos, but that's a different story!

 

Thank you; that's the query answered.

 

The ROD's were popular on the GWR line to Radstock

 

Possibly, but they were still non-standard on the LMS (as indeed, the GWR) and maintenance and spares availability would heve been an issue. The LMS bought 55(?) simply to canibalise for spares for those in the working fleet. By the late 1920s, recession was on the horizon and there was less need for heavy goods engines, so non-standard types went first. They had a short life on the LMS, whatever the reason. The last one went in 1933

 

The LNER O4/3 class were ex ROD 2-8-0s. There are three O4s preserved in New South Wales, Australia; ROD 1984 and ROD 2003 both at Dorrigo & ROD 2004 at Richmond Vale. To have three preserved in that area, did the Aussies have access to more spares to keep them going?

Hmm idle thought; if funding can be found for two A4s to be shipped across the Atlantic for an 18 month visit, how about a loco which operated here, but we don't have any examples of in this country coming over for a year?

 

63601?

 

Thanks for that; I didn't realise it's a /3

 

Well.. as you are probably aware 63601 is an 8K, later O4/1. As I see it, the ones in Australia aren't O4/3's, as they were never owned by the LNER to get that classification... frankly, as you're probably aware... interesting as they may be, they aren't different enough from the O4/1 to stir up enough interest, and frankly an O4 (lovely as it is!) just doesn't have the mass appeal! Given that all of the O4/3's are in fairly rough shape (none even close to steaming)... I don't see anyone stumping up the cash to make it happen.

The only way I could see it happening would be if it was a one way trip.

 

To get back to the question in the thread heading...

They are a post 1948 enhancement to enable people to quickly identify shunting locomotives. When followed by a 6, you know it is likely to be a big red shunting engine.

 

Actually, the '4' prefix never caught on with the men, who always gave the correct LMS number. BR management tried to get them to use it with the slogan, "May the 4s be with you."