Could Mallard's speed record have been broken?

[ScotTrainLad]

Could Mallard possibly break her original record of 126 mph under certain circumstances like modifications, straight tracks, etc? How fast could it possibly go?

 

[hexagon789]

Could Mallard possibly break her original record of 126 mph under certain circumstances like modifications, straight tracks, etc? How fast could it possibly go?

Duddington himself said he thought 130mph was possible.

In those days there was a low permanent speed restriction at Grantham, which hampered building speed to climb the bank - had that not existed, then keeping up a higher speed at the summit would in theory have given the potential to attain a greater speed by the foot of Stoke Bank all other things being equal.

A redesign of the valve gear might have also mean the middle cylinder bearing didn't have a tendency to run hot under strain which was the reason Mallard herself failed at the end of her record run.

 

[Bevan Price]

Given a suitable location, a Stanier "Duchess" and a rebuilt "Merchant Navy" could probably also have broken the record.

A "Duchess" reached 114 mph, but at a rather dangerous location (Betley Road on WCML), but had to brake rapidly on the approach to Crewe; if it had been travelling any faster, it might have derailed when it reached the pointwork near Crewe. As it is, its reported 57 mph approaching Crewe was risky. (It was almost 50 years before Crewe was remodelled to permit higher speeds.)

 

[Spamcan81]

Duddington himself said he thought 130mph was possible.

In those days there was a low permanent speed restriction at Grantham, which hampered building speed to climb the bank - had that not existed, then keeping up a higher speed at the summit would in theory have given the potential to attain a greater speed by the foot of Stoke Bank all other things being equal.

A redesign of the valve gear might have also mean the middle cylinder bearing didn't have a tendency to run hot under strain which was the reason Mallard herself failed at the end of her record run.

The middle big end was largely solved by a redesign in BR days. The rest of the motion remained fit for purpose.

 

[hexagon789]

The middle big end was largely solved by a redesign in BR days. The rest of the motion remained fit for purpose.

Bill Hoole did take 60007 up to 112mph in 1959, with 400 tons on the drawbar (Mallard had only about 240). Hoole would've liked to have gone faster but Alan Pegler told him to ease off.

Perhaps the track was still not quite at full prewar standards.

 

[Harvester]

Bill Hoole’s climb up Stoke Bank on 23/5/1959 after a fast run through Grantham, was much steadier and controlled than Joe Duddington‘s was with Mallard. Topping the summit at 75 mph with good boiler pressure 60007 was perfectly placed for a very fast run down the bank. However with two inspectors on the footplate, Bill had little option but to ease off when told to do so at 112mph!

 

[Townsend Hook]

Hopefully it won’t be too long until the replica Pennsylvania Railroad T1 is completed in the USA and can have a crack at the record, it seems to be making good progress!

 

[Harvester]

The middle big end was largely solved by a redesign in BR days. The rest of the motion remained fit for purpose.

Interestingly Mallard had to come off at Peterborough on 3/7/1938 with a hot middle big end! On 23/5/1959 not only did 60007 reach 112mph down Stoke Bank, but Bill Hoole managed another ton south of Peterborough on level track. The next day 60007 was available for work, and the following day took out the down Flying Scotsman from Kings Cross!

 

[Taunton]

For the maximum boiler throughput and generation of steam, they really should have started further north, and had two firemen. It was a bit simplistic, despite all the preparation of the special test train, to just turn it on the Barkston triangle, north of Grantham, and hope to just accelerate straight off in a few miles. It had been standing at Barkston for some time with no steam demand. Starting further north, and with a detailed assessment of boiler throughput and steam generation, should have really seen them start the run at Retford, or even Doncaster.

Were the records ever published of the boiler pressures during the run?

 

[randyrippley]

Could Mallard possibly break her original record of 126 mph under certain circumstances like modifications, straight tracks, etc? How fast could it possibly go?

Something to remember was Mallard was just four months old, just completed running in, was the first experimentally fitted with a Kylchap exhaust and - allegedly - had been specially prepared with polished / smoothed steam passageways and cylinders when the record was set. Somewhere I've read that Gresley had her earmarked as a "special" while she was being built with extra care taken to assure smooth running.
It would be a bit much to expect another loco - or even Mallard - to be simply taken out of regular service and attempt to emulate the run. The boiler would be less efficient, steam passages less optimised, even the bearings would be worn. If you tried it now it would even be a different boiler and cylinders - would these even be built to the same spec as Mallard's were?

 

[Harvester]

Were the records ever published of the boiler pressures during the run?

Not sure, but Joe Duddington’s driving method was! The temporary speed restriction at Grantham was troublesome, with Mallard going through the station at only 24 mph. To reach the summit at the required 75 mph Mallard was worked hard with a fully open regulator and 40% cut-off for most of the climb, then with cut-off eased slightly to 30% near the summit. It must have been back breaking work for Firman Thomas Bray with the shovel? In comparison on 23/5/1959 Bill Hoole drove 60007 through Grantham at 75 mph and easily held this to the summit with high boiler pressure, due to excellent work by his Fireman Alf Hancox.