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Thursday, April 11, 2013

Steam Engine Progress - Transportation

Steam engines for transportation, which began with the original Trevithick locomotive in 1804, advanced continously until phased out by more modern technology.

Toward the end, steam locomotives were using high and low pressure steam, uniflow cylinders, superheated steam, and (due to massive steam production) mechanical stokers.

Below is a drawing and cutaway of a late-model steam locomotive.  I found a couple of things on the cutaway interesting:

Item #10, a superheater.  Takes advangage of heat remaining in the exhaust gas to increase efficiency.  Item #12, a blast tube.  Spent steam that is exhausted from the cylinders goes into a venturi.  The expanding steam entrains exhaust gas from the smoke box and pulls it out the stack.  This puts the fire side of the boiler at a negative pressure and pulls massive amounts of air into the firebox, burning the coal much faster than if it were allowed to smolder.  Much simpler than installing fans for the same purpose.

Elements of the locomotive 1. Firebox 2. Ashpan 3. Water (inside the boiler) 4. Smokebox 5. Cab 6. Tender 7. Steam Dome 8. Safety Valve 9. Regulator Valve 10. Superheater Header in smokebox 11. Piston 12. Blastpipe 13. Valve Gear 14. Regulator Rod 15. Drive Frame 16. Rear Pony Truck 17. Front Pony Truck 18. Bearing and Axlebox 19. Leaf Spring 20. Brake shoe 21. Air brake pump 22. (Front) Centre Coupler, 23. Whistle 24. Sandbox.

Meanwhile at sea, where there is a bit more room to indulge your need for power, a photo of RMS Titanic's starboard steam engine, and her boiler room:

This is about as far as piston-driven steam engines went, with regard to transportation.  Marine engines were replaced with steam turbines in the early 20th century, while it took until the mid-20th century for the steam locomotive to be replaced by the diesel-electric locomotive.

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