"Boosters" on steam engines

[Anonymous]

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?

[tree68]

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!

[Anonymous]

QUOTE: Originally posted by tree68

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.

[CSSHEGEWISCH]

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.

[PBenham]

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.

[Anonymous]

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?

[selector]

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.

[adrianspeeder]

So how did they work exactly?

Adrianspeeder

[Modelcar]

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.....

[John Krug]

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.

[Anonymous]

I found this picture, with the drive axle being on the far right

[Modelcar]

That's a good rendition of the mechanicals of the booster system

[eastside]

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.

[Anonymous]

QUOTE: Originally posted by eastside

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.

[eastside]

QUOTE: Originally posted by Lotus098
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.

[Anonymous]

QUOTE: Originally posted by eastside

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 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.

[Anonymous]

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!

[Anonymous]

QUOTE: Originally posted by futuremodal

off topic

Hey, AntiGates, I And why does your 10 car train need three 3-axle locomotives to pull it? Your horsepower to tonnage ratio must be staggering!

[Modelcar]

....With that length of train you may have to add engines if you encounter much gradient....Pretty neat....!

[eastside]

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.

[Anonymous]

QUOTE: Originally posted by Modelcar

....With that length of train you may have to add engines if you encounter much gradient....Pretty neat....!

Lining up all the cars into a perfectly strainght line is the hardest part.. once I have a single "picture" of an entire train, making it '"move" down the picture of the track is actually the easy part.

The short train length of the original train isn't due to an oversight on my part, rather if I had a train the size of the bigger one, moveing at the speed of the slower one, the total file size would be so huge that it would be killing the forum users having to use a dial up web service

[Hugh Jampton]

QUOTE: Originally posted by eastside

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.

They probably did it for safety reasons,, steam is hot and you dont want it exhausting just any old where.

[Anonymous]

QUOTE: Originally posted by eastside

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.

That's why the big train isn't in my signature. Though the mechanics of "train building" might make the smaller train seem 'foolish" because of it's short size, the realities of web mechanics make the reason for the shorter train abundantly clear

Or, you can right click on the picture , and select "block images from this server" and you'll be all set [:D]

[eastside]

QUOTE: Originally posted by TheAntiGates
Or, you can right click on the picture , and select "block images from this server" and you'll be all set [:D]

Interesting, wasn' t aware of that one, but that blocks individual signature images. The way to block images in signatures from all posters is through the forum profile settings:

"Do you wi***o view members signatures when reading posts?
Do you wi***o view images in posts, such as smilies and posted images?"

[Modelcar]

Gates...I'm on dial up and neither one of your "trains" bothered me in opening it up...

[Anonymous]

QUOTE: Originally posted by eastside

QUOTE: Originally posted by TheAntiGates
Or, you can right click on the picture , and select "block images from this server" and you'll be all set [:D]

Interesting, wasn' t aware of that one, but that blocks individual signature images. The way to block images in signatures from all posters is through the forum profile settings:

"Do you wi***o view members signatures when reading posts?
Do you wi***o view images in posts, such as smilies and posted images?"

True man,...I was just trying to be helpful, out of concern that you might have found MY sig offensive due to its size, and just wanted to block my signature, but not everybody elses... using the setting you mention would block EVERYBODY's signature...

[Anonymous]

QUOTE: Originally posted by Modelcar

Gates...I'm on dial up and neither one of your "trains" bothered me in opening it up...

Well, thanks man, that' good to know.

but for the record, the reason why my train is "overpowered" could be:

a) I cut the train short out of concern for impact on dialup users
b) Broken knuckle , the crew is asleep and the brake line is fouled
c) surplus power move

Anyone can take their pick

back to boosters, After the guys here got me smart enough to know what to look for, I found that Wikipedia of all places, has a good explanation, worth reading.

[GP40-2]

QUOTE: Originally posted by TheAntiGates

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?

The C&O generally seemed to be a fan of boosters on their later engines.

The T1 2-10-4 was booster equiped for a total starting TE of 108,625 lbs.

The J3a 4-8-4's (#614 is an example) had a booster and could produce 80,700 lbs. starting TE.

However, the mega-boiler 2-6-6-6 Allegheny did not have a booster, and was limited to 110,000 lbs starting TE from its drivers. High speed HP was another story...

It is interesting to compare the N&W 611 to the C&O 614.

Both locomotives are 5000 HP machines. The N&W decided to not use a booster, but instead use smaller drivers and a higher boiler pressure to allow the 611 to produce its 80,000 lbs starting TE. The downside to this design is more stress on the steam system from the high pressure, and higher piston/drive line speeds due to the smaller wheel diameter. The N&W J was also reported to be a rather slippery engine from concentrating so much TE on only 4 axles.

The C&O went with larger diameter drivers and a lower boiler pressure+a booster to allow the 614 to produce its 80,700 lbs TE. With this approach, the C&O 4-8-4s were reported to have a very high level of adhesion, and often would stall out on a hard pull rather than spin their drivers. The downside to this approach is the high maintenance required for the booster truck. High enough that Ross Rowland disconected the booster while operating the 614 in excursion service.

Really, there is no easy way to get low speed power out of a steamer with few drive axles. Both the N&W and C&O designs had good point and bad points.

Some RR's stayed away from boosters like the plauge. The B&O relied on "the more powered axles, the better" design for their mountainous routes. They relied on their fast S1 2-10-2's (85,000 lb TE, 70+MPH top speed), EM1 2-8-8-4's (115,000 lbs TE, 70+ MPH top speed) and their older, and slower EL class 2-8-8-0 simple articulated (120,000+ lbs TE, top speed limited to 55-60 mph) for freight service.

In the end, N&W's/C&O's/B&O's varied designs to this problem lost out to the diesel-electric, which allowed both high starting TE and high speed HP in a single design.

[TomDiehl]

The Boston & Maine #3713, a Pacific Type being rebuilt at Steamtown has a booster trailing truck that's also being rebuilt for operation. A booster trailing truck is a self contained steam engine that will power the axle(s) of the trailer. It has separate controls in the cab and its own steam supply and exhaust. The exhaust steam being directed to other cylinders for use is a compound or Mallet type locomotive, which showed up for a short time in the early 20th century, but quickly fell out of favor due to lowered top speed, and the shear size of the secondary cylinders. Steam is exhausted through the stack to create a draft for the fire, but where else would it go? At least this way it is used for a purpose.