Crost boilered BR 2-10-0 from Golden Arrow/Bachmann

[TheWeatheringMan]

As mentioned in my earlier post on my Duke of Gloucester model here is a description of my Franco-Crosti boilered 9F - a topical subject in view of Hornby's recent announcement of a 'Railroad' range version of this locomotive.

 

As most will know a small batch of 10 Standard 9F's were built in the 1950's with the Italian designed Franco-Crosti boiler which featured a pre-heater drum (not a boiler) beneath the main boiler (which was slightly smaller in diameter than a conventional 9F boiler (see below)). The idea was that the otherwise waste heat emitted from the chimney was diverted into the pre-heater drum before being emitted from a repositioned chimney. The plan was to use this otherwise wasted heat to pre-heat the feed water on its way from the tender to the main boiler and thus effecting a saving in coal used to boil the water.

The ten locomotives were allocated to Wellingborough shed for use on mineral trains.

 

Although the idea was in theory a good one - and in fact the Italian State Railway converted or built a fairly large number of locos that were actually reasonable succesfull the ten BR locos were a notable failure.

 

Although the designer of the Franco-Crosti system promised BR savings on coal and would have received royalty payments once BR obtained these savings in actuall fact he never received a penny from BR owing to the promised savings never occurring.

The locomotives proved something of a disaster for BR - the two main problems being a human one and a practical one.

1/ The side mounted chimney much closer to the cab resulted in the exhaust surrounding and being sucked into the cab causing a great deal of discomfort for the footplate crew, not to mention the safety aspects of the driver's vision being impared. An attempt to remedy this by fitting a smoke deflector alongside the side chimney was of little help.

2/ Because the exhaust gases were cooled by being passed through the pre-heater drum sulphuric acid condensed from the gases in the secondary smokebox and caused rapid rotting of the metal.

 

Due to these problems the locos spent a lot of time out of service and were eventually taken to works and made into conventional locos - this entailed blanking off the pre-heater drum and fitting a blastpipe in the front chimney so as to make the locos work conventionally.

Before describing my model a few points should be noted :

 

1/ : Upon conversion to conventional working the pre-heater drum was blanked off not removed as it was constructed effectively as a part of the main boiler structure.

2/ : After conversion and due to the smaller diameter main boiler the locomotives were sometimes rated as being of 8F power rather than 9F - there is conflicting information on this and the fact that the conversions were seemingly used turn and turn about with 'normal' 9F's seems to indicate they were treated as 9F and yet the smaller diameter main boiler would suggest that a lower steaming rate would drop them to 8F.

3/ : Due to the main boiler being a smaller diameter it is not possible to convert a model of a 'normal' 9F into a Crosti - many years ago Messrs Crownline did such a conversion for the then Hornby 9F (I have never seen the kit) but I have been told it retained the Hornby boiler - if this was the case then the resulting model would never look right - I would be interested to know for sure, especially if my information is wrong so that I can be corrected.

 

On the the model:

 

Although the Golden Arrow resin kit was designed to fit the tender driven Hornby 9F my model was made by using a modern Bachmann 9F loco as the base - I cannot see any reason why the GA kit should not be used with a modern Hornby loco-driven 9F and talking this over with Chris Meachen at GA he has said he sees not problem in this.

 

As I did with my Duke of Gloucester I cut the cab from the Bachmann body and the GA kit and mounted the Bachmann cab onto the GA body. I then carefull removed the footplate from the GA so as to allow me to mount the GA boiler into the Bachmann footplate thus retaining the chassis fixings of the Bachmann donor.

The chimney of the GA was replaced by the one from the Hornby Britannia that was the donor for Duke of Gloucester.

The detailing, pipes etc. were taken from the Bachmann body together with some of the GA parts plus some scratchbuilding.

The tender is the Bachmann model repainted.

The model has been heavily weathered to reflect the condition that these locos usually ran in prior to conversion.

All in all I feel that the model does capture the look of a Crosti very well - lets hope that Hornby are tooling up a new body and not making their Crosti by modifying the existing 9F for the reason stated in 2 above.

 

Please feel free to ask if you would like more information about my model or methods.

 

Regards,

 

Robbie

[TheWeatheringMan]

The remainder of the pictures.

[bike2steam]

Are you sure ?? I think you'll find that on conversion to conventional working the pre-heater drums were removed, and after a few years in store were scrapped at Crewe works. 

This is my model (mistakes 'n' all) of 92029 built 30 years ago from a Crownline conversion kit, recently received a new Hornby loco-drive chassis.

[TheWeatheringMan]

Hi

Thanks for your reply.

I said what I did about the pre-heater drum based on something I read a good few years ago and a conversation at Wolverton Works with an ex Crewe fitter who worked on the conversions - I was a guard at the time working stone trains to Wolverton that originated at the quarries near Westbury - we used to work via Oxford and Bletchley and reverse the trains via a stub of the old Newport Pagnell branch that formed a triangle the opposite side of the WCML to the works. We would then wait time / take a break in sidings across from the works just north of the underpass if memory serves me correctly before working back via the same route.

 

I have gone and had a look at my books that cover the 9F's and when seen broadside on it is very clear that the daylight visible under the boiler of the ex-Crosti locos makes it very obvious that the pre-heater drum had indeed been removed.

I cant remember where I read what I did - probably in a magazine and I'd have to say the fitter I was talking to could well have been mistaken.

 

All in all I have to acknowledge that my comment was in error and I'd like to offer you my thanks for pointing it out and to apologise to Members for my almost misleading them.

Regards,

Robbie

 

PS:

 

Very well done on your conversion and thankyou for sharing the picture - I know now that although the old Crownline kit could not overcome the boiler diameter matter it isn't that obvious on a completed model.

Isnt the new Hornby loco drive chassis superb for the money - especially at Railroad prices. I have in stock, soon to start, another Golden Arrow Crosti and a Bachmann 9F ready do build a converted loco - all I need now is a giesl chimney and i'll also do 92250 so I've covered all the variations except the 'Tyne Dock' 9F's - and I'm not ruling out one of those appearing!!.

Regards,

Robbie