What are those fairings I see on each side of steam locomotive smokeboxes? Are they to help with aerodynamics? I mostly see them on locomotives hauling passenger trains. Thanks. Jason
Jason,
Yes, they help with aerodymanics in a fashion. Primarily intended to force the smoke up and away from obstructing the view. I don’t know how effective they were. Some railways liked them, others didn’t use them.
The red fairings in the photo are what you mean?
John’s explanation is correct, but rather than “fairings” the correct term for these is “smoke lifters,” for obvious reasons. They are also referred to as “smoke deflectors.” You’ll also sometimes see them called “elephant ears” because of their appearance. North American railroads that used smoke lifters on at least some engines included the Boston & Maine, Canadian National, Delaware & Hudson, Lehigh & Hudson River, Maine Central, Milwaukee Road, New York Central, Nickel Plate Road, Union Pacific, Wabash, and Western Pacific. Smoke lifters were most effective at higher speeds, which was why they were mostly used on passenger engines. The Union Pacific’s 4-8-4 no. 844 still operates with the smoke lifters applied to it in the late 1940s. So long, Andy
Mark Newton, on another thread, pointed out that smoke deflectors were usually applied to locomotives with low back pressure steam exhaust systems, where the outflow of steam couldn’t be depended upon to carry combustion products above the cab.
They aren’t restricted to high speed locos. All but the most ancient Japanese steam locomotives were fitted with smoke deflectors, and most of them were restricted to a maximum speed of 70KPH - a speed which few of them ever reached. (Some war-built JNR locos had smoke deflectors built up from wood planks, which says a lot about both the wartime steel shortage and the necessity for smoke deflectors on those particular locos.)
It isn’t obvious from photos, but the edge-on view from the cab has almost no effect on visibility.
Chuck (who has a lot of locos with smoke deflectors)
Thanks Chuck,
Mark would know better than I do. In Australia NSW had them on only one loco that I know of. That was as an experiment, and since the rest of the class was not fitted I suppose there was no marked benefit found in the trial.
However, Victorian Railways made extensive use of them. Even on some locos that would never work up enough speed to make the things effective as far as I can see. According to Mark’s explanation the Vics must have had a low back pressure characteristic. I don’t know what coal they burnt, but NSW coal is better quality than the Vic stuff in general. (I come from NSW). Some of the VR R class (as shown in the photo in earlier post) burnt oil, but they still had the smoke deflectors whether they burnt oil or coal.
Sorry I missed the other thread. I am only a learner. Mark is the guru.
Sperandeo wrote: <“Smoke lifters were most effective at higher speeds, which was why they were mostly used on passenger engines.”> That’s highly arguable. Smoke deflectors were most effective on locomotives with streamlined front ends optimised for low exhaust steam back pressure. It just happens that most of the modern US passenger locos of the railroads you mention had such front ends. The D&H, Milwaukee, NYC and UP all did a lot of work on improving front end design, and applied their findings to fast and not-so-fast locos. As Chuck noted, the majority of JNR steam had smoke deflectors, and they weren’t all high-speed passenger power either. But they did have beautifully designed and built front ends - JNR steamers typically have very soft exhausts, but steam freely. Look too, at the many European locos with Giesl ejectors and deflectors. They weren’t all express engines. Cheers, Mark.
bush9245 wrote: <“In Australia NSW had them on only one loco that I know of. That was as an experiment, and since the rest of the class was not fitted I suppose there was no marked benefit found in the trial.”> John, you’re refering to 3673 I assume? From talking to one of Mr Cardew’s cadet engineers, I learned that the trials were reasonably successful, but the conservative and rather miserly NSWGR hierarchy were unwilling to approve the wholesale conversion of the class on cost grounds alone. <“However, Victorian Railways made extensive use of them. Even on some locos that would never work up enough speed to make the things effective as far as I can see. According to Mark’s explanation the Vics must have had a low back pressure characteristic.”> They did - the so-called “basher” front end. It was a modified Master Mechanics design, with a four-orifice blastpipe cap and quite large steam and exhaust passages. <“I don’t know what coal they burnt, but NSW coal is better quality than the Vic stuff in general.”> Mate, you’re not wrong. VR burnt a lot of that awful brown, semi-lignite rubbish from Yallourn, which I wouldn’t put in my fireplace… <“Sorry I missed the other thread. I am only a learner. Mark is the guru.”> Thanks for the compliment, but I wouldn’t go that far! I’ve just been lucky that most of my railway career has been with steam, and I’ve learned a bit along the way. But there are some marvellous old blokes I’ve worked with, who have forgotten more than I’ll ever know. They’re my gurus! Cheers, Mark.
tomikawaTT wrote: <“They aren’t restricted to high speed locos. All but the most ancient Japanese steam locomotives were fitted with smoke deflectors, and most of them were restricted to a maximum speed of 70KPH - a speed which few of them ever reached. (Some war-built JNR locos had smoke deflectors built up from wood planks, which says a lot about both the wartime steel shortage and the necessity for smoke deflectors on those particular locos.)”> Absoultely correct, Chuck. The JNR had front end design down to a fine art! But then, their steam locos were in all respects well designed and built. Cheers, Mark.
Expanding on what MarkNewton said:
Older Steam engine desings had their smoke stack exhaust well above the boiler section, which allowed the exhaust to maintain its upward motion even in a moderate headwind. Late model designs utilized boilers with maxed out boiler dimensions that resulted in the exhaust exiting just above the top of the boiler. This made it easy for the airstream to push the exhaust plume right on top of the boiler and stay there in a manner similar to the way air would adhere to the surface of an airfoil. The “elephant ears” disrupted this airflow adhesion in much the same way spoilers disrupt the lift on an airplane’s wing so that it can descend in a nose up or straight attitude. Otherwise, it would litterally have dive (with its’ nose down) towards the runway.
Yes. Here’s a couple of C36 pigs without deflectors. I didn’t really fancy the look of the modification.
Preserved and prettied up.
The way they finished out their service life. The top express engine in the 1930s hauled freight in the 1960s.
That’s a nice photo of '42 at Sydney Terminal, John. I’ve only ever fired her on a couple of trips, but I had a real soft spot for her. One of those trips was a joint 3801Ltd/NSWRTM job to Canberra to meet up with 1210 - we had to split engine and tender at Queanbeyan to turn her to come home. Then we had a fire under the cab at Bungendore, waiting to cross the Canberra Xplorer. What a trip! The B&W photo of '09 on the trip train is a beauty - it looks like it was taken at Bridge Road, Homebush? Cheers, Mark.
Leon Silverman wrote: <“Older Steam engine desings had their smoke stack exhaust well above the boiler section, which allowed the exhaust to maintain its upward motion even in a moderate headwind.”> The exhaust velocity is largely dependent on exhaust pressure, not the physical dimensions of the stack or chimney. Don’t confuse what happens in a 100’ high powerhouse stack with a locomotive. I’ve fired an engine with a Lempor-type front end and a very tall stovepipe funnel - the exhaust was quite soft and prone to drift down over the cab even at full regulator and long cut-offs. Having a tall stack made no difference. <“Late model designs utilized boilers with maxed out boiler dimensions that resulted in the exhaust exiting just above the top of the boiler.”> Again, a misconception. Older locos usually had high mounted blastpipes and short petticoat. Newer locos had low blastpipes and long petticoats. The overall dimensions from blastpipe cap to to stack rim were about the same. Cheers, Mark.