The LNER Encyclopedia

Came across this video on youtube: http://www.youtube.com/watch?v=csCAmGhC ... re=related and Bittern looks to be going way faster than 75mph, possibly approaching 90mph . Was the speed limit ignored to get the train up to Durham or is it really going no faster than 75mph?

blackout60800 wrote:Came across this video on youtube: http://www.youtube.com/watch?v=csCAmGhC ... re=related and Bittern looks to be going way faster than 75mph, possibly approaching 90mph . Was the speed limit ignored to get the train up to Durham or is it really going no faster than 75mph?

I don't think they would dare do faster than 75, seen as even before the mid week ban on the ECML, Network rail do keep there weary eye on steam.

Remember, most people have GPS and it would be easy to record if the loco was doing faster than 75....severe penalties would follow if this was to be the case for sure!

Ay up!

Looking at the rate at which the axleboxes are passing the camera, I reckon 70-80mpm - no faster.

It is often said that science is the art of measurement. So in the case of the speed of 4492 as shown in the YouTube clip, I timed the passage of the 12 cars of the train. I found that these 12 cars passed in about 8 seconds. A coupled Mk 1 coach is 66.85 feet long. So a 12 car train is 66.85 x 12 = 802.2 feet long. Travelling this distance in 8 seconds gives a speed of 802.2/8 = 100.3 ft/sec. Converting the speed in ft/sec to mph, 102.2/1.46, gives a speed of 68.9 mph.

So somewhere in the region of 70 mph is correct for the speed of the train in the YouTube clip.

Sir Brian

Thanks very much

May I add, the speed is recorded by what is essentially a black box in the locomotive - and in a few very rare occasions in the last decade, drivers have lost their jobs for exceeding the speed limits on steam locomotives in particular circumstances.

There are few exceptions to the speed rule, I recall (though I could be grossly wide of the mark) in certain sections you can be within 5% of the actual limit, above or below, and in mainline proving runs, locomotives are required to exceed the speed up to 10% above their designated top speed (75mph for all of the Pacifics) as part of their clearance to run on Network rail metals.

But in short, anything about 75mph is extremely unlikely, regardless of what's on the front.