Gresley 10000 'Hush Hush'

[neildimmer]

Evening All

I have been given a photo of the experimental Gresley W1 No. 10000 "Hush-Hush" was the only 4-6-4 tender locomotive to run in Britain. It included a number of experimental features including a marine type water-tube boiler working at 450psi. Although this original design is usually dismissed as a failure due to the revolutionary water-tube boiler, No. 10000 did successfully work a number of high profile trains. No. 10000 was completely rebuilt and re-entered service in 1937 with a conventional boiler and A4-style streamlining. Both before and after rebuilding, No. 10000 never carried a name, although it was often referred to as the "Hush-Hush" due to the initial secrecy of the project.(info courtesy of LNER Encyclopedia)

The photo is not very good but i have included it for histoical content

10000 'Hush Hush' Just after passing Tweedmouth on a Edinburgh-Newcastle relief (Photographer unknown courtesy of the facebook site Railways of Berwick and the Eastern Borders)
http://railway-photography.smugmug.com/ ... &k=SbxZSs3

Here is the photo i have of the rebuilt 60700

60700 Kings Cross (Gresley 3-cylinder conventional locomotive rebuild of experimental high-pressure four cylinder compound with marine type water-tube boiler introduced in 1929 Hush Hush) August 1957 Kings Cross
http://railway-photography.smugmug.com/ ... &k=VkDQBdn

Neil

[2512silverfox]

Quite well known photo of 10000 in its original condirion. My PC has Loco Publishing Co as copyright holder although to be fair they absorbed many photos (including officials) without acknowledging the source!

[Deepol]

Quite well known photo of 10000 in its original condirion. My PC has Loco Publishing Co as copyright holder although to be fair they absorbed many photos (including officials) without acknowledging the source!

Yes, I've a copy of that somewhere as well. The other shot of her when she became 60700 is very interesting indeed as I don't think you see many of her as that. Having said that the two photos are super. I love seeing all these shots of yours Neil.

[52D]

Apparently the original pic was on a glass negative and badly scratched, from research two possible candidates for the photographer have emerged one was a Mr Romanes a Chemist from Duns, Berwickshire and the other WJB Sanderson forgive me if i have Mr Sandersons initials wrong. Both men were friends and were active in railway photography around the area at the time.
I have seen a lot of Mr Sandersons work but only a few of Mr Romanes and would like to track down more examples.

[markindurham]

The original boiler wasn't 'that' big a failure, of course. After removal from 10000 during the rebuild, it was the works boiler in the Stooperdale shop at Darlington for many years

Mark

[Blink Bonny]

Ay up!

Although it is true to say that the boiler's leaks were well publicised, it would be interesting to see how many leaks were repaired on the "conventional" boilers in use elsewhere.

No 10000's main failing was that she failed to prove more economical than the conventional engines, burning more coal and consuming more water. The leaks were part of the problem but it also suffered from low superheat, poor draughting and the fact that her boiler was long and thin. Marine type boilers tend to be better when they are approximately cube shaped.

The chassis was a success but, it has to be said, Gresley's only compound. A brave experiment that fell short, but not through any lack of effort on Gresley's and Bullied's parts.

[john coffin]

some interesting stuff, but important to get a couple of things correct

W1/60700 was actually a 4-6-2-2, the first trailing axle being a Cortazzi and the rear one being a Bissell truck,
both of which were requirements of Gresley after many early modifications to the design, since the original had been laid out as a Pacific, to undertake its basic aim which was to see whether this kind of boiler could compete against the A3's which were still at that time, quite heavy coal users.

By the time, the engine was sent in to traffic, the first stages of the reductions of coal consumption had been installed for some time.

The real problem with Hush Hush was that the kind of boiler was not really designed for the intermittent usage that a railway engine has to undertake. Ship boilers produce steam for long times, and the are rarely pushed to high speed use often, whereas railway engines had at that time considerable changes in their speeds in a journey between say KX and Doncaster. Remember this was the first time a boiler such as this was placed on a railway engine, so everybody had to undertake a large learning curve.

I was lucky enough to see it once a KX in the 50's and it was certainly imposing even in rebuilt form, must have looked stunning in original.
paul

[61962]

The original concept for 10000 was to improve on the economy of conventional locomotives. The first design was based on a K3 chassis, but it was found very quickly that this was too small for the boiler and it soon became a pacific. Gresley wanted it to be better than the A1s which were the current LNER express locomotives and that became the stated goal. After Yarrows found they needed more space the accommodate the required 25000lbs an hour steaming rate the chassis became the 4-6-2-2 we all know. In service the stated goal was achieved, the engine using 20% less coal than the A1, but by this time the A3s were in service with long travel valves and 220psi boilers and were 30% better in coal consumption than the A1s, so 10000 was already out of date when put to traffic. A lot of money was spent trying to equal the performance of the A3s without ever approaching them.

After fitting of the double Kylchap exhaust the coal consumption increased significantly, and although the performance improved it was too little too late.

The boiler was troubled with air leaks in the enclosing casing although there is no indication that there were problems with leaks in the boiler tubes. Yarrow put a lot of effort into solving the casing leakage problems by introducing expansion joints but were not entirely successful and were still involved as late as 1932.

10000 was not the only water tube boilered locomotive to be constructed. A freight engine was built by Alco in the USA for the Delaware & Hudson Railroad before 10000 was conceived and worked for many years along with a second higher pressure version built in 1928.

Eddie

[richard]

My understanding was that the Delaware & Hudson locos were very efficient but also a bit on the slow side, designed for heavy mineral use.

The LNER had 50 or so other water tube boiler locomotives: the Sentinel Y1, Y3, and Y10 types; plus the Sentinel railcars.

Richard

[john coffin]

Interesting that the guys in America who made that water tube loco specifically for long heavy goods trains, which was probably a better use of the steampower, since it tended to be, in America, longish non stop journeys, rather than UK short runs with slacks and so on, actually devised the Mallett style locos a different kind of loco to the Beyer Garrett.

Paul

[61962]

The LNER had 50 or so other water tube boiler locomotives: the Sentinel Y1, Y3, and Y10 types; plus the Sentinel railcars.

Richard,

The Sentinal boiler was not technically a water tube boiler. It was a "conventional" vertical boiler with an internal firebox, so the fire and hot gasses were surrounded by water. It's rapid steam generation and high output were due to the many water tubes that criss-crossed inside the firebox. The true watertube boiler is enclosed in a dry airtight casing rather than being enclosed by a water jacket as the Sentinal and the conventional "Stephenson" boiler.

Gresley was partly attracted to the Yarrow type boiler by it's lack of stays, which were the Achilles heel of the locomotive type boiler, requiring the services of boilermakers for their replacement in service, and often being the reason locomotives were withdrawn for overhaul as only a limited number of stays could be allowed to be replaced on shed. Much of the maintenance of 10000's boiler could be done by less skilled and therefore cheaper men than the boilermakers.

Eddie

[richard]

Eddie,

Thanks for the correction. The Sentinel boilers are usually described as "water tube" - even by the likes of Yeadons, which is where I got it from. It sounds like a bit of a hybrid, and I'm guessing the name may have originated from Sentinel themselves to describe their slightly different boiler.