Hello,

With the recent thread on "speed and old school tech", I would like to add the following and forgive me if it has been sighted previously.

I just purchased my January 2008 copy of "The Railway Magazine" (a UK publication). In addition the feature article on the grand opening of Saint Pancras station in London, inaugurating the new high speed connection with the channel tunnel, HS1 (High Speed One), there was an article suggesting the HS1 operators may be open to a steam speed run on this line which would have to be east of the London tunnels and obviously west of the channel! Apparently by January 1st, 2010 there may be allowance for one open access path an hour for "outside trains" such as the French TGV or German ICE.......or a high speed steam run.

Mr. Mitchell mentioned the TGV in a previous post followed by Mr. Rowland's reply of "never say never". It appears there may be a chance for this to happen. Albeit they are suggesting 100MPH to start but it would obviously pave the way for a subsequent run that could break the Mallard's 126 MPH record.

This presents some interesting challenges. Aside from building a new locomotive to reach this goal (very, very expensive), which locomotive preserved could reach it? May I suggest the No. 71,000, Duke of Gloucester? Let's consider two critical issues, fast valve events and balancing.

As for valve events you need fast events. Here is a video of the Duke, turn your volume up:

http://video.google.com/videoplay?docid=4227871634151512750&q=71000&total=284&start=70&num=10&so=0&type=search&plindex=5

Notice hardly a hint of rhythm or patterns, simply sequential valve events one right after the other. Realizing two cylinder American steam may have the same sound at high speed, could they push-it further for prolonged and repeated runs? The Duke has triple cylinders and Caprotti poppet valve gear.

Balancing is another challenge. David Wardale suggested in his Red Devil book that a three cylinder locomotive can be effectively balanced to eliminate overbalance altogether? I have not personally done the analysis as confirmation but it is an interesting thought and if feasible could be applied to the Duke. Yes, you could import the 4449 or 844 to run on that line but they are absolutely massive as compared to typical British steam power. Plus their overbalance could hammer blow the meticulous track structure of HS1. After all, if you don’t want your champagne to quiver in your glass while riding on the 186 MPH Eurostar, there had better not be any blemishes on your track structure!!

Here is the web site for the Duke if you want read further on its features:

http://www.dukeofgloucester.cwc.net/

The best I can make out form the spec diagram, it appears the Duke has got 74" diameter drivers.....not super large by any means. However, if overbalance if off the table, they may do fine.

I recall from reading an old article in...I believe the "Central Headlight" the publication of the New York Central System Historical Society, that the NYC had done high speed wheel slip tests...maybe on a Hudson?? They greased the rails and filmed the drivers. I believe they reached 140 MPH wheel speeds and at one point, the drivers lifted from the rail when the overbalance force reached the same level as the axle load. Lifting slightly is one thing, having the flange clear the railhead could be absolutely frightening.....especially on a slight curve!

The Duke would provide a platform that could be used for ongoing excursions beyond just a speed run, plus it would be more cost effective. A one-piece cast steel bed frame like used on the C&O 614 would help keep things tight but the Duke's conventional construction could be tidied up for a special run.

Of course, you may want to x-ray your driver castings and tires prior to the run so they don't explode when you reach 145 MPH.

......food for thought and my own opinions for what they are worth!

Cheers!

Randy Musselman

Perhaps in Europe, but I can't imagine this happening stateside. Running a train for the sole purpose breaking a speed record would be fraught with a whole truckload of risks, mechanical, operational and of course LEGAL. Can you see the headline?

The Duke would certainly seem to have the capability get close to Mallard's record. It's basically a similar locomotive with the advantage of having Caprotti rotary cam poppet valve gear. The engine has also been "tweaked" during its original restoration (correcting a couple of original defects including an undersized exhaust system and undersized air openings in the ash pan) and it's been tweaked again in subsequent overhauls (cylinder heads internally recontoured to improve steam flow, brick arch angle and height revised, new cams to allow for increased expansion fitted). The Mallard did have the significant advantage of functional streamlining.

The A1 "Tornado", a new 4-6-2 presently nearing completion in the UK, might be in the ballpark too.

Probably the best prospect for beating Mallard's record is Wardale's proposed 5AT project. It's a 4-6-0 based on the British Rail Class 5 but with all the thermodynamic and mechanical improvements that Porta and Wardale came up with over the last ~60 years incorporated. Its design speed is 125 MPH and it's intended for routine operation at 113 MPH (180 kph). This engine's highly streamlined steam circuit, large, double piston valves, long travel Walschaerts valve gear, dual Lempor exhaust system, and streamlining would no doubt make it capable of beating Mallard's record IF it ever gets built.

According to Wardale this engine will have little or no reciprocating balance despite the fact that it has only 2 outside cylinders. The lack of reciprocating balance allows perfect rotational balance to be achieved which would be highly desirable in a high-speed locomotive.

This engine will be designed using a combination of proven steam locomotive practice (such as AAR standards and Baldwin's design guidance) AND current state-of-the-art methods such as Finite Element Analysis (FEA) and other computer modeling techniques. As a result, they'll be able to say with a high degree of confidence at what speed the engine can safely be operated once it's built.

Read more here: http://www.5at.co.uk/