Crosti boilers and use of steam pre-heating water feed. . . . . . . . .
Those of us living in York might be familiar with Treasurer’s House, a National Trust property near the Minster. Treasurer’s House is very old, in parts, but was extensively remodelled and filled with an eclectic mix of antiques by its owner, Frank Green, in the 1890’s. What’s this got to do with railways? You might well ask. Well, Frank’s wealth came mostly from his ancestors who invented the ‘economiser’, a means of pre-heating water for steam boilers. Hundreds of these ‘gadgets’ were built at their factory near Wakefield, mainly for factories in the UK and around the world.
Over in Europe in the 1930’s Messrs Attilio Franco and Dr Piero Crosti were polishing their final design for pre-heating water feed to steam locomotive boilers. It had been done in various ways many times before, of course, but the Franco-Crosti boiler was unusual in using not just steam to heat the water, as in ‘the economiser’ for example, but steam and exhaust gases (i.e. smoke). Roll the story forward and in 1955 British Railways took 10 of their new 9F locomotives and fitted them with Franco-Crosti boilers. A shrewd move or madness? Or something locomotive engineers call ‘fiddling about’?
The teenage cognoscenti spotting on the Midland Mainline would occasionally see one of these locomotives, (‘crusties’ as we called them), trundling around a curve and into view at the head of a rake of coal wagons, blasting out exhaust, not from the conventional chimney (only used when lighting up the locomotive from cold) but from a sort of chimney half way down the boiler on the right hand (fireman’s) side. And a strange sight they were.
It didn’t work. Someone, wondering why the idea hadn’t caught on in days gone by, might have realised that any sort of water leak would put water and coal smoke together to create nitric acid, with unfortunate consequences for any metal nearby. Crusties were soon converted back to the conventional by blocking off the water pre-heater system and creating a conventional locomotive, albeit an unconventional looking one.
A few years ago I met up with Don who had experience of firing Crusties before and after conversion. Don: ‘I remember taking a coal working up the Market Harborough to Northampton line on a test run, they said. We were on one of Wellingborough’s Crostis. There were single bore tunnels on that line and it was frightening in the tunnels. You couldn’t see anything for smoke and there were bits flying off the tunnel walls. When they inspected the tunnels after a few months it was certain they were damaging the brick work so they were banned from the line.’ I asked him what they were like in more conventional form. ‘Not much better’, he said. ‘They were b****** to get the pressure up. On 9Fs you could move them around the yard with only about 70psi but not a Crosti. They were so under powered I think they downgraded them from 9F to 8F. They made the shirt stick on your back if you were firing them’.
The Crusties, along with everything else vaguely linked to steam, went to the great Motive Power Depot in the sky en mass in autumn 1967.
Of course, long after Don’s interview, like so many others I have done, strange questions are left lingering. Let’s suppose the Stephensonian concept of steam locomotive design had not been the chosen one.
Let’s suppose Crosti had been around sooner. Let’s suppose side mounting exhausts were the norm rather than exhausting though the top of the locomotive. What then? How much of the built railway system was predicated on exhausting through a top mounted chimney? What might it all have looked like instead?
Just a thought.
And, by the way, Frank Green died in 1954 aged 93 having left Treasurer’s House – but no economiser - to the National Trust in 1930.
If you want to see what a Crustie looked like check it out here
‘Polyphemus’
John Swanwick
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