Steam & Excursion > This Steam Giant Is Moving About In It's Natural Habitat!

ALCO turned out the 10 "Little Mallets" for the Western Pacific in 2 batches of 5 each 7 years apart with the first 5 being built in 1917 at their Dunkirk plant and the last 5 being built in 1924 at their Richmond plant.  Despite the separation in time and the different plants, these 2-6-6-2's were nearly all identical.

They were first built to handle the freight traffic between Oroville and Portola, California through the famous Feather River Canyon.  They proved quite adept at this service until 1931.  At that time, with the coming of the first batch of 2-8-8-2 from Baldwin together with the opening of the Northern California Extension that ran the 112 miles between Keddie and Bieber, this resulted in the 10 2-6-6-2's being reassigned to the NCE.  For the rest of their service days they would be found operating out of Keddie and north to Bieber and back.

In this fine view, we see #207, the 2nd of the second batch of "Little Mallets" leaving the Keddie roundhouse to get ready for another trip north to Bieber.  She would continue in this service until finally being stricken from the WP roster in 1951 and sent to Luria Brothers for scrapping in Pittsburg, California.

For now, let's enjoy seeing her at work in her natural habitat.

Martin



Edited 3 time(s). Last edit at 10/15/20 01:15 by LoggerHogger.

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Thanks for this great picture, as always, Martin.  Did this locomotive have slide valves on the low pressure engine and piston valves on the high pressure engine?  How common was that?  Gerry

Very, it was easy to get a large port area on the slide valve reducing the back pressure on the
low pressure side.

Out 

With all of the curves in the canyon you have to wonder why WP put the headlight on the smokebox front and not on the top of the air tank on the pilot deck so it would follow the track.
Mother Nature liked to drop lots of rocks on the tracks of the Feather River Canyon!

Awesome image of an awesome steam locomotive.  

GPutz Wrote:
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> Thanks for this great picture, as always,
> Martin.  Did this locomotive have slide valves on
> the low pressure engine and piston valves on the
> high pressure engine?  How common was that? 
> Gerry

That is the cylinder setup on all Mallets, by definition. Well, maybe a few compounds were built with all piston valves, but rarely.

-LD



Edited 1 time(s). Last edit at 10/15/20 14:03 by LarryDoyle.

LarryDoyle Wrote:
-------------------------------------------------------
> GPutz Wrote:
> --------------------------------------------------
> -----
> > Thanks for this great picture, as always,
> > Martin.  Did this locomotive have slide valves
> on
> > the low pressure engine and piston valves on
> the
> > high pressure engine?  How common was that? 
> > Gerry
>
> That is the cylinder setup on all Mallets, by
> definition. Well, maybe a few compounds were
> built with all piston valves, but rarely.
>
> -LD

The USRA Mallets had piston valves on both the high and low pressure cylinders.

PHall Wrote:
-------------------------------------------------------
>
> The USRA Mallets had piston valves on both the
> high and low pressure cylinders.

The piston valves on the low pressure cylinders were apparently too small, because in the development of the Y-class engines, which were based on the USRA design, the Norfolk & Western increased their diameter from 14" to 18."  That change increased the speed of maximum power from 15mph to 25mph.

Edit:  Additional changes contributing to the improved performance included revised port design affecting lead and lap, and larger nozzle and stack, which reduced backpressure while still achieving the required draft.

Edit#2:  The need for super large piston valves at N&W goes back to the original question about slide calves, and callum_out's comment that it was easy to get large port area with a slide valve.  Plus I might add that lower steam pressure and temperature reduced the common slide valve problems with pressure force imbalance and lubrication.



Edited 2 time(s). Last edit at 10/15/20 20:53 by Elesco.

Many of the Baldwin logging Mallets had piston valves on both the high pressure and low pressure cylinders.

Thanks to everyone for the information.  Gerry

Number 207 has a Cole trailing truck, typical of Alco locomotives of the era.