Steam Locomotive Walschaert Valve Gear Animation
Based on 4-6-2 Pacific, Soo #2714: images, data

Steam Locomotive Valve Gear Animation Here's a larger version, with 'color coded steam' and sound.
(Warning: 254K GIF, 0.6 minutes @ 56kbps)
An even larger version with animated cycling of the cutoff and reverse linkage action.
(Warning: 549K GIF, 1.3 minutes @ 56kbps)

...Why?!  It's just an experiment to try to satisfy a fascination held with this mechanism (Walschaert valve gear 54K GIF) since childhood (late '40s).  Whatever...

By the way, Walschaert gear is correct; Walschaerts gear is not (unless it is used in the possessive case, with an apostrophe, eg: "Walschaerts' design"). The inventor's name was (Egide) Walschaerts (pronunciation: ay-gee-da val-sherts), but the design was patented under the name Walschaert for political reasons. Ref: Publications Style Manual,  Pennsylvania Railroad Technical and Historical Society.

Some of these illustrations my help answer the question: "How does a steam locomotive work?".

For thermo techies, here's a Steam Engine Pressure-Volume Diagram. (43K GIF)   Why are the main driver counterbalances not symmetrical? (29K GIF)   Cut-away illustration of a steam locomotive's internal workings. (77K GIF)

See some of the controls in a locomotive cab. We enhanced this boiler backhead image (70K JPEG) with labels for our friends at the Danbury Railway Museum (CT).

Images created on a Macintosh with Canvas 6.01 and animated with GifBuilder 1.0 .
These GIFs can be found on many pages around the web. This site is the originator of these images.

Links (Locomotive, Steam, Walschaert)...
Comprehensive data and history of North American steam locomotives [History of Pacific type]
Locomotive Boilers and Engines
1920 Purdue University treatise on locomotive boiler and engine design, construction, and operation (San Diego RR Museum). Includes a Walschaert Gear page.
Steam Engine Valve Gear On The Computer
Downloadable freeware simulations of every kind of valve gear you've ever heard of by Charles Dockstader (CA). We're Mac heads here, but we downloaded his .exe files and borrowed a Wintel machine to try them out and were impressed with this work; very cool and enlightening.
Locomotive Basics - valve gear
Text and JavaScript diagrams of the Walschaert gear. Also Valves & Pistons (lap & lead), and Cylinder design (PV indicator) (UK)
Steam Engine Slide Valve Animation
Valve timing diagrams with lap & lead illustration (UK)
Railroad Paint Shop
Line drawings (GIFs) of locomotives [steam loco drawings]
Collection of AutoCad Line Drawings of U.S. Locomotives. Link to a 1.3M "Drive Assembly" (Walschaert gear) AVI animation file.
I can't read the Japanese characters on this site, but it's worth the trip for the Big Boy valve gear illustrations.
Baker Locomotive Valve Gear
Richard Leonard's page of historic Pilliod Co. spare parts catalog -- one should be able to figure it out from the "page 4" and "page 14" images.
How do we get make-up water into an operating high pressure boiler? Here are some sites that explain "How does a steam injector work?"...
UK Heritage Railways - Injector Magic
Bluebell Railway - How the Injector Works
Locomotive Engine Running and Management - Injectors
Walschaert Valve Gear - Wikipedia Encyclopedia
Wikipedia Encyclopedia is using several of our images on this page.
WP Loco - A Virtual Guide
Explains the working of a typical steam locomotive with interactive Flash animations (that have recognizable roots in several of our illustrations here). Very nicely executed.

(& Links)
4-6-2: #2714
Steam Engine
PV Diagram
Mac made Last tinkered with April 20, 2013
by Bob:
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