I’m totally at a loss here. From time to time i’ve read about “booster axels” on stream engines, incorporated into either the trailing truck or onto the tender, and this sounds like a great idea.
but, now exactly is power transfered to the wheels in such a scenario? I get a mental image of some sort of steam lines and a turbine impeller, but that is based upon nothing.
What is the real deal behind boosters?
IIRC, they were/are steam/piston driven, just like the main drivers, but obviously smaller, and were coupled through gears to the boosted axle. They could be engaged and disengaged at will, and were only used to increase tractive effort at low speeds. As for how (and if) cutoff was adjusted, well, I don’t know!
Okay, thanks, so it was mostly something to break the train free from a dead stop? Makes sense.
Tender boosters could also be found on some 0-8-0’s. They were useful in starting a heavy train as shown above and were also useful on passenger trains for smooth starts. One of their weaknesses was that they consumed a lot of steam and the engineer had to be aware of that to avoid running out of water.
Boosters became popular with railroads that needed a little extra “oomph” to get a train started. They were most frequently found on high horsepower/ super power engines, which below 30 MPH,sent a good deal of usable steam out the stack. Erie had them on their 2-8-4s, for example, Lehigh Valley put them on 2-10-2s,2-8-2s and 4-6-2s in a dual service role (albeit briefly). PRR wouldn’t be caught using such things, Pennsy being Pennsy,naturally. A fair number of terminal lines had tender boosters on their 0-8-0s (BRC,IHB,TRRA,Union).The Union then had 0-10-2s that could wrestle any contemporary train into motion. Passenger users were most notably NYC as well as UP. The oddest example, had to be on L.F. Loree’s Delaware& Hudson, when he went to some extreme lengths to squeeze every ounce of tractive effort from his 2-8-0s, running up to the ultimate multi-cylinder/booster equipped engine of them all, the 4-8-0, L.F.Loree (D&H 1403) . Too bad it left Schenectady in 1932. (about the worst possible time to roll out an “obsolete” locomotive,but at the time,who knew?) Lots of railroads would experiment with boosters, usually with marginal results.
So then I’m guessing there was an auxilary steam throttle valve specific to the boosters? and a one pipe connection between the engine and the boostered tender ?
I guess most Berkshires featured boosters? How about some of the bigger engines that C&O used?
CPR’s 2-10-4 Selkirks also had boosters, and they modified one so that it could use steam at 850 pso for that booster, a third cylinder located between the outer ones. That loco (#8000), a one-time experiment, also had a three part boiler, and steam was transferred from one part to another at 1600 psi…I’m not kidding. It ran fine, but the crews were exhausted from running ‘puckered up’ due to their distrust of the loco. It scared the he** out of them.
So how did they work exactly?
Adrianspeeder
Adrian…I’m seeing told some of the boosters were 2 cyl’s. and somehow connected to the trailing truck or tender truck with gearing…I’m not sure just how that was accomplished…I thought perhaps a cyl. was installed between the wheels and driving a crank shaped axle but perhaps not…and yes, in most cases, they were used to acquire more traction to start a heavy train…
I’ve heard that the boosters were only good until 15 to 20 MPH. There was a time when Pennsy borrowed some Reading T-1 northerns which were equipped with boosters. A friend of mine who knew a Pennsy engineer said that they loved that feature (among others) on the T-1’s for starting their heavy trains.
I found this picture, with the drive axle being on the far right
That’s a good rendition of the mechanicals of the booster system
Go back through the threads and you’ll find another thread on boosters that I started.
http://www.trains.com/community/forum/topic.asp?TOPIC_ID=23644
What I never got a good answer for was the first one. Why the locomotive designers routed exhaust to the extreme opposite of the locomotive, i.e. right next to the stack. That was a lot of extra pipe.
I believe that was done so that the steam, like the stuff from the main pistons, pulled more air through the fire. So that the more steam you use the more steam you create, even then locos were equipped with a blower, which, as far as I know, simply blew steam up the stack, to pull more air. I think this was used at low speeds or when the loco was standing.
I’m not clear on what you mean. If you’re saying that putting the exhaust for the booster near the chimney added to the draft, it seems unlikely because the booster exhaust is too far away. The NYC Hudsons are typical examples. Besides, if that’s what they wanted, the designers would have joined it to the main exhaust.
I was wondering the same thing. And while I sure don’t ’ know, I would guess it may have something more to do with distancing the booster working loop from the outlet to atmosphere, to prevent cold air form getting into the lines and possibly start a hammering condition?
I’ve seen hammering in stationary boilers, and it’s not a pretty condition. Just a guess though.
off topic
Hey, AntiGates, I was wondering if you could throw in a few Auto-Max cars into your little train animation there?[^] And why does your 10 car train need three 6-axle locomotives to pull it? Your horsepower to tonnage ratio must be staggering!
…With that length of train you may have to add engines if you encounter much gradient…Pretty neat…!
AntiGates, wonderful animated gifs, but have you checked their sizes? The images alone are about 710 kb total. For someone on dialup interested in interacting with the forum simply viewing a thread could put a crimp on his participation.