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Notes and summary: steam locomotive

Short answer

A steam locomotive's boiler surrounds fire-tubes with water, and a strong draught evaporates water rapidly. Steam is superheated to dry it and prevent power loss, then enters the steam-chest where slide valves direct it to push the piston back and forth. Exhaust increases draught, and a connecting rod and crank convert reciprocating motion into wheel rotation.

After taking notes, write a summary of the following passage in about one third of the words of the original. From the date of the introduction of the steam locomotive about 130 years ago, there was a continuing increase in the size and weight of trains. [passage of about 520 words on the working of a steam locomotive: boiler, fire-boxes, super-heater, steam-chest and cylinder] ... The reciprocating action of the piston is changed into a rotational movement of the wheels by a connecting rod and crank.

Notes

Title: Working of the steam locomotive

  1. Background: over about 130 years, trains grew steadily bigger and heavier
  2. Boiler
    • Two fire-boxes (inner and outer) extend far forward
    • Inner fire-box linked by tubes to front fire-plate
    • Almost all heating surface (incl. fire-tubes) surrounded by water
    • High evaporation needed; strong air draught blown over fire
  3. Super-heater
    • Steam passes through it to raise temperature and dry it
    • Wet steam causes loss of power in cylinder
    • Gives required power at lower pressures
  4. Steam-chest and cylinder
    • Superheated steam goes to steam-chest on cylinder
    • Slide valves open/close ports in turn
    • Steam pushes piston one way, then the other
    • Exhaust leaves through blast pipe, increasing draught
  5. Motion: piston's back-and-forth action becomes wheel rotation via connecting rod and crank

Summary

Since the steam locomotive was introduced about 130 years ago, trains have grown steadily larger and heavier. In a steam locomotive, the boiler has inner and outer fire-boxes that extend far forward. Almost the whole heating surface, including the fire-tubes, is surrounded by water, and a strong draught of air is blown over the fire so that water evaporates rapidly. The steam then passes through a super-heater, which raises its temperature and dries it, because wet steam loses power in the cylinder; superheated steam gives the required power at lower pressure. From the super-heater the steam goes to the steam-chest on the cylinder, where slide valves open and close the ports in turn, so that the steam pushes the piston first one way and then the other. The exhaust steam escapes through a blast pipe and increases the draught. Finally, a connecting rod and crank change the piston's to-and-fro motion into rotation of the wheels.

(About 170 words, about one third of the original.)

✓ Answer checked by Claude Opus 5.5 (high effort)

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