Considering the year Mallard very nearly reached that speed in Lincolnshire on her Historic Run, I wonder how many people know she very nearly failed with wheel bearings on the point of disintegrating from the heat friction
My favourite A4 has always been Bittern, i was around 12 years old i believe when i saw her come thundering through Hornsey on an UP Express at full power and believe me you can keep all your deisels and electric loco's, These were REAL engines and needed a REAL crew to drive them.
I agree that the A4s were magnificent machines but their main weakness was the derived valve gear for the inside cylinder. When properly maintained it worked well but if it was a bit 'off' it could cripple the locomotive.
For my money, George Churchward was a far superior designer and innovator than Gresley. Admittedly the A4 was better than the GW Kings in the 1948 trials but the Castle beat the A3 in the earlier exchange and Gresley used the knowledge gained better than Collett.
Churchward was the first of the modern locomotive designers with his experiments at the beginning of the last century as he was taking over from Dean and his ideas influenced many of the other design offices, notably at Ashford and Crewe.
Richard. (Great Western Nutter)
I only started this thread cause the music thread was getting all clogged up with railway engines, buses & fire appliances. 
