What improved?
Streamlining reduced air resistance. Three cylinders turned the driving wheels beneath the blue casing.
THE ENGINE ROOM / 14
Small parts. Big discoveries.
A little steam. A clever machine. Let’s see what makes it move.
ON THE WORKBENCH4-6-2 · Streamlined A41938 · 4-6-2 · Streamlined A4
Explore the steam history timeline
3D MODEL
MallardBlue No. 4468 is shown with its original-style wheel valances. Cutaway removes the casing to reveal the machinery. The activity is an air-resistance experiment, not a driving simulator.
Drag to turn · Scroll or pinch to zoom · Right-drag or two-finger drag to panTap a part to discover it
Ready when you are
FROM THE HISTORICAL RECORD · 1938 · 4-6-2 · Streamlined A4
THE ENGINE’S STORYMeet Mallard
On 3 July 1938, Mallard reached 126 miles an hour. That became the world speed record for a steam locomotive. Its smooth casing helped it push through the air. The record also needed a skilled crew and carefully prepared machinery.
Original, replica or teaching model?
Read the source Blue No. 4468 is shown with its original-style wheel valances. Cutaway removes the casing to reveal the machinery. The activity is an air-resistance experiment, not a driving simulator.
How did life change?
Fast trains became symbols of modern travel. Behind the glamour were people who fired, drove, cleaned and repaired them.
In the archive
Select a photograph to look closer. Captions distinguish originals, replicas and related examples.
LNER A4 No. 4468 Mallard outside the National Railway Museum, York.
PTG Dudva · CC BY-SA 3.0Archive record ↗
YOUR NEXT DISCOVERY
Look closer. Have a go. Find out.Think like an engineer.
The wind-tunnel workshop
Use the wind tunnel. Compare shapes at the same speed, then discover why going twice as fast takes much more effort.
Choose a shape, set the speed to 30, and aim for air resistance below 300 units. These are comparison units, not measurements of Mallard.
At twice the speed, this simple model gives four times the air resistance and eight times the power needed to overcome it.
No timer. Try as often as you like. These puzzles explain ideas; they are not instructions for operating a real engine.