About 20 miles north of here, on the all-electric route to Glasgow, is the Bushey (Hertfordshire) curve. It's an "S" bend that engineers aboard British Rail express trains treat with respect. They take it at 80 miles an hour, the official speed limit.
But on this test run the sleek new Advanced Passenger Train (APT) takes the bends at a clean 125 m.p.h. Not only that, but the soup doesn't spill from the bowls in the dining car and the coffee barely ripples in the cup. The chairman of British Rail, Sir Peter Parker, dangles a pocket watch on a long chain.
Through the curves it remains perpendicular to the floor, indicating that the tilt, 13 degrees in some instances, exactly compensates for the speed around the bends.
The APT, 14 years in the making and currently the most technologically advanced train in the world, is to be brought in service on the curve-filled London-to-Glasgow run at around Christmas. It is capable of cutting the time over the 400 serpentine miles from 5 hours to 4 hours and 10 minutes, including stops in between.
In the mid-1960s, British Rail took a somewhat controversial stand: It would develop a superfast train that could use conventional track, tight curves and all, unlike other nations, which were developing fast trains that would require specially laid track.
The doubters said it couldn't be done. The answer came: "Let's try."
The initial design team drew on conventional railroad engineers and on many from the aerospace industry as well.
Besides front and rear streamlining, smoothing out the side profile became important, too. Doorknobs had to be recessed and window projections all but eliminated. Below 80 m.p.h. this is not so important, but above 100 m.p.h.it becomes vital.