Oil Firing.

I'm not sure how the idea of converting a different boiler would be needed or that it would be a permanent or even semi-permanent arrangement came about. Many British engines have been converted for oil fuel going back to the 1920s. Several, including GWR ones, were converted during 1947 when that looked the way ahead. It was quickly found that it wasn't and they were soon converted back to coal firing.

There are modifications needed when going over to oil but they are not structural. They involve some changes to the ashpan, dampers, brick arch and firehole doors, then the addition of firebricks inside the firebox to protect some bits from the fierce flame. The hard part is finding a decent and dependable burner.

 

Unfortunately, as has been mentioned previously, copper boxes are not really suitable for oil firing and both 2873 and 4965's boilers have copper boxes. If Tyseley really are considering converting 4965 to oil then it will be interesting to see how they go about it.
Ray.

 

Indeed. There is a chapter of Holcroft’s book about his experiences with oil firing in 1921 and again 1926. The SECR adopted a system based on Derby practice, and with a kit of parts provided from the main works, conversion was said to take 18 hours and reversion to coal firing only 8. Now obviously that is with the correct components to hand and a running shed full of skilled fitters, but the general point is that the conversions were comparatively simple jobs that could be done by a running shed; not something only attempted at major overhauls.

One interesting practical point he notes of the system adopted was that the burner required a supply of steam to operate. So the equipment had provision for that to be supplied by another loco until pressure had reached about 30psi, after which the oil-fired loco could provide its own steam. Not too much of an issue back in the day, but it would be a bigger issue in a modern context where the oil fired loco may be the only one in steam in a given day.

Tom

 

Think that I remember being told that you can use compressed air to "light up" until there's enough steam pressure to run through the "atomiser"

Both the Festiniog & Rheidol have done coal to oil and back to coal conversions.
I know the former used waste oil - some of it absolute rubbish - for a prolonged period and the latter new oil [diesel ?] - this is going back several decades ! I can still remember the pong some of the Dukesonian mixtures would emit when working hard, and I was at the back of the train and not subjected to the rigours of the footplate in that era. The Alco [Mountaineer] could be regarded as notorious in that area.

 

Did the oil burning Halls and 28xx have steel boxes back in the day?

 

Yes, quite possibly. The context of Holcroft's writing was that the steam was needed to provide atomisation, so presumably compressed air would work as well. He wasn't talking about using it to pre-heat the oil, which is also necessary if you use very viscous oil as your fuel.

Tom

 

I don't claim to be an expert, but I don't think they had steel fireboxes. AKAIK they had standard No.1 boilers.

 

No. Steel boxes were a rarity on Britain anyway and going to oil fuel was made on standard copper boxes. As I've pointed out previously, the copper boxes in the Middle East 8Fs weren't worried by oil firing. I don't know if the GWR ever used steel boxes but I've never heard of it if they did.

 

AFAIK in BR days the VofR used a shore based compressed air supply for 'starting' purposes

 

For some first hand experiences of oil fired steam, admittedly on a ship

https://national-preservation.com/threads/being-a-stoker-on-the-ss-freshspring.1421219/

 

A couple of points about this oil firing lark, if I may be permitted as someone who knows very little about it.

The issue that Tom raises about the need for a steam supply surely refers to the heavy Bunker C type oil used in Holcroft's day before lighter oils became more readily available.

As regards to the issue of copper fireboxes these can indeed be converted for oil firing. However they are unlikely to have as long a service life as a steel box as copper reacts less favourably to the rapid temperature changes involved. This was acceptable post war when boiler overhauls and renewals were an established part of steam operations but best avoided in a preservation context given the high cost of replacing copper boxes. Steel is easier to repair and cheaper to replace, but that said, you can convert a copper box if you so wish.

One interesting issue that arose when locos were converted from coal to oil was the fact that they soon found that superheater elements were getting badly burned at the firebox end because without a brickarch the fire was being drawn part way down the fluetubes. The solution was to reduce the length of the elements.

This at least is my understanding of the situation, but please correct me if you think I'm talking rubbish.

Peter