STREAMLINED DUCHESS BACK ON MAIN LINE

RESTREAMLINED LMS 4-6-2 No. 6229 Duchess of Hamilton will be hauled by Deltic King’s Own Yorkshire Light Infantry from the National Railway Museum at York to the Locomotion museum at Shildon on Thursday. See facebook.com/heritagerailway for more details and timings.

 

Just out of interest, what is 46229's prospects of running on the main line with the wind armour on? Would the drifting smoke problem that saw blinkers attached to the Big Lizzies also manifest itself on a streamliner?

 

No, it was never a problem with the streamliners.

 

No; it wasn't perceived as a problem with the non-streamliners until 1945 or so when they started putting deflectors on, by which time the streamliners were being destreamlined anyway. Now that it is recognised as a problem, it needs a solution. I can hardly think that the addition of streamlining would help lift exhaust from the chimney.

 

I'll repeat: it was never a problem with the streamliners, the aerodynamics of which are totally different from a non-streamliner. The flat front of the conventional smokebox has the effect of pushing the air outwards and upwards as the engine moves at speed. This means that there is less air alongside and above the boiler, creating a partial vacuum there which draws the exhaust down into that area and the driver's view. The streamliners, as was supposed to happen, disturbed the air far less and so there was no low pressure area and the exhaust was not drawn down.

As built, the non-streamlined engines had little problem either; it was the fitting of double chimneys resulting in a lower exhaust pressure, which failed to lift the gases above the low pressure area, which initiated the problem.

 

Patience Ralph, Im sure it'll be only a matter of time till Hamilton is back in anger, there's too much temptation to let it loose in streamlined form to ignore for too long.

 

But that depends on the support and effort from the Director; with Srteve Davies's departure there is a question of what the future NRM policy will be - both on main line running and the necessary engineering support.

 

I'll have to dig out the article but somewhere I read an article that claimed the casing on the LMS streamliners was less efficient at lifting the exhaust than the casing on the A4s. Something to do with the LMS casing being dead level along the top as opposed to the curve of the A4s.

 

In case anyone doesn't know, move on Thursday is caped. However, 55002 has been involved with some shunting at the NRM today, which meant it worked on the mainline for the first time in 30+ years. 60009 was also used for the shunting, which included moving 60008 from the wagon works to the sidings outside the great hall.