Booster engines

Could you fit a booster to a cab-forward?

If so, which end would it go on?

I presume you are reffering to the SP 4-8-8-2?
It looks like a good candidate.
That four wheel truck under the cab is probably supporting alot of weight so there could have been a fair amount of TE available. I doubt powering a single axle as on the rear end of the SP engine, would be justifiable.

I think Eliphaz's reply sounds about right. And I think the Southern Pacific was one of the railroads that DID use boosters on many locomotives. Problem, though, is that the benefit would have been minor. Trailing truck boosters tended to give about 15,000 pounds added tractive force at starting. On a reasonably high-drivered 4-6-4 or 4-8-4 with a tractive effort of 45,000 or 60,000 pounds (I'm thinking, here, of New York Central Hudsons and Niagaras) this isa significant boost. On an articulated freight engine with eight driving axles, the effect would be proportionally much smaller.

Boosters were sometime put on tender trucks instead of the trailing truck of the locomotive. This allowed the booster engine to be geared to three or four axles, and might have allowed a higher "boost" to the tractive effort. The cab-forwards were, however, intended to haul freight over the Rockies,and so would have been designed for good low-speed tractive effort using the main engines: my guess is that Southern Pacific didn't think the added complexity of booster engine was justified.

Still... On the other side of the continent, the Norfolk & Western had (cab-in-the-normal-place) articulateds, the Y6 2-8-8-2, which they used for moving coal over the Alleghenies: excellent engines, of a design perfected over several decades, able to give very high tractive effort with no fancy business, and they STILL thought a "booster" was worth adding. Instead of gearing a separate engine to one or more truck axles, however, their "booster" was an arrangement for using high-pressure steam in the forward engine: the Y6 was (unlike SP's modern cab-forwards) a compound, using low pressure steam most of the time in its forward engine.

Hi

is there any preserved locomotive with trailing truck booster (working or non working condition) ?

Several years ago I visited the museum in Baltimore but forgot to investigate this detail on the No. 490.

Thank you for any reply.

IIRC, Berkshire KS 2916 has a booster. I forget where it's stored, but if you dig online, you'll find her. C&O 614 also had a booster, but it was removed a while back.

The Greenville (PA) Railroad Museum has a former Union Railroad 0-10-2 #304 on display. There were nine of these locomotives in the class, this is the only survivor. Originally built for the Union Railroad, a former US Steel railroad that served the Pittsburgh, PA area, it went to the Duluth, Missable and Iron Range Railroad, also a former US Steel subsidary. The locomotive was numbered 604 on the DM&IR. It now carries Union Railroad paint on one side and DM&IR paint on the other as a static display.

More on the museum and displays: http://www.greenvilletrainmuseum.org/

I looked at a number of sources but I'm afraid this is the best photo I could find showing the tender booster:

http://www.railpictures.net/viewphoto.p ... 680&nseq=0

Fan Railer wrote:IIRC, Berkshire KS 2916 has a booster. I forget where it's stored, but if you dig online, you'll find her. C&O 614 also had a booster, but it was removed a while back.

Thank you! Meanwhile I contacted the guys from the C&O 614 and they confirmed, that the 614 has again a booster and it works up to 20 mph.

Two question remained. Does have the #490 a booster.
The second question is what is the difference between a normal booster and the high speed booster (mentioned in the Franklin description).

Thank you!

Hi

The SP only used Booster engines only on (3) types of engines , AC-1 4000 - 4016 , 2-8-8-2's rebuild from older class MC-1 &2 from compound to single expansion .
Next is 2-10-2's class F-4 3668 -3717 F-5 3718 - 3769
Next and last 4-10-2's three cylinders SP class 1,2,&3 5000 -5048 , all the rest of the locomotives No Boosters . Pat.

Don't think any of SP's AC-1s had a booster on the engine-- they tried a tender booster on a couple of them, it seems.

Anyone know how long the 4-10-2s kept their boosters?

Other SP engines had boosters, of course-- 4-8-4s, a few 4-4-2s, some 4-6-2s, all the 4-8-2s except the EP&SW...

Does anybody knows the operation of the booster? How did they engaged them and what was the procedure to disengage them?

railfilm wrote:Does anybody knows the operation of the booster?

No, not really - but from my theoretical knowledge... maybe this helps - but I would be glad if someone could correct it.

How did they engaged them and what was the procedure to disengage them?

Well, Boosters come from "starters" or "turners" - huge engines, usually stationary steam engines cannot start by themselves, because having no starting valves like in locomotives. So to start such multiple expansion engines you'll have to turn the high pressure piston in a starting position, usually 10 to 30 degrees after top death point.
This was done with huge levers, which were clicked in, and notched the flywheel around bit by bit, or later with so called starter engines.
Some marine engines were kept slow turning when in port, just to ensure optimum lubrication of of the shaft bearings and the often huge gears, thus here small steam maintenance engines, so called "turners", were fixed to the main engine frame, able to turn the main crank shaft slowly for maintenance, and also to ensure lubrication of the bearings of the main shafts.
Both steam engines were coupled in to a cog wheel. The cog geometry was so designed, that if the starter or turner was running faster than the main shaft - thus power flow from the auxially engine to the main engine flowed, the power was properly transfered. So we have the front face of the cogs of the starter or turners pushing against the back side of the cogs of the main shaft cogwheel, transfering the power. But as soon as the main engine or main shaft was running faster, the front face of the cogs of the cogwheel on the main shaft pushed the back face of the cogs of the starter or turner cogwheel, and because of the different cog geometry this pushes the cogwheel of the turner or starter out of traction.
So in boosters you have the same.
The engine starts, and a spring loaded system holds the booster in traction.... the engine speeds up, and as soon as the locomotive speeds exceeds the turn limits of the booster engine, the main axle cogwheel uncouples the cogwheel of the booster on the same system, as the cogs pushes the cogs from the booster shaft cogwheel out of traction, and releases the lever lock which is spring loaded - the booster unlocks quick and with no further mechanical need. Manually disabling of the booster is allways possible, just releasing the spring loaded system, and the cogwheel of the booster gets uncoupled and the booster is shut off.

The booster engine turned a gear, and the axle had a gear-- those two gears never meshed, in the US anyway. To engage the booster a third idler gear shifted into position to "connect" the other two gears.

Thank you very much for the explanation!

SP 4449 has a tender booster which is rare in itself and probably the only operational one in the world. First time I climbed in the cab was over 55 years ago when it was stuffed and mounted as a display engine and the last time was around 10 years ago on a private tour.