A4 'Bittern' at 90 mph

[John Ashworth]

Britain's mainlines are becoming heavily congested and pathing steam trains (currently restricted to 75mph/120kph) is become very difficult. Early this morning A4 pacific No. 4464 Bittern was tested at 90mph on the Great Western mainline from Didcot to London in anticipation of more general high speed running in the future. As there is a 10% tolerance it is highly likely that 100mph/160kph was reached.

Videos at:

http://www.national-preservation.com/th ... 337/page-6

http://www.youtube.com/watch?v=ycJkfaHA ... r_embedded

[John Ashworth]

And a different A4 story:

Steam engine landmark celebrated at the National Railway Museum

In a scene not witnessed since the 1930s, the record-breaking Mallard has been reunited with its sister locomotive, the Dominion of Canada, to mark 75 years since it became the world’s fastest steam engine...

[Steve Appleton]

As there is a 10% tolerance it is highly likely that 100mph/160kph was reached.

Since a tolerance is normally equal on both sides of a measured value (eg 90 mph +-10%) then it is just as likely that the speed achieved may have been as low as 81 mph (130 km/h) and still been within tolerance!

[John Ashworth]

Another video: http://www.youtube.com/watch?v=me1OfEEKk3I

The 6.2 mile section between Maidenhead and Slough was completed in 4 minutes, an average of 93MPH.

[John Ashworth]

And now on the ECML:

4464 at 90mph! The Ebor Streak 29-06-13

[John Ashworth]

Video: ‘Bittern’ steams in to claim its own rail record

Bittern arrives at York railway Museum ahead of Great Gathering

[Philip Martin]

That Bittern video is certainly professional looking. Thank you, John.