If Isaac understood, why don’t we?

If a body,  or indeed a railway train is travelling at speed, there are only two forces acting upon it; the engine’s torque, diverted through gears to the driving wheels providing the forwards motion, and inertia, which is the force attempting to keep that same railcar stationary. If a third force is then introduced, attempting to turn the railcars’ forward motion to one side, there is a set set of mathematical calculations which determines how much the railcar can turn without being overtaken by the first force, which is the momentum provided by the engine. If the momentum exceeds the mathematical certainty of the turning, or centripetal force, the rail car will come off the rails, and crash, owing to the force acting upon the railcar.

See the Wimbledon crash, where the driver fell asleep at the controls, and the speed of the railcar or tram was too great to let the railcar take the bend safely; or one of many possibilities why the Amtrak train failed, which is where the railcars’ speed was said to be possibly at least twice the set speed for the rails curving into the bend at that point.

3 comments for “If Isaac understood, why don’t we?

  1. Errol
    December 19, 2017 at 8:35 pm

    This is why you automate it. You take the ability for the driver to make a mistake away from them. Long before the turning, there should be controls that trip in software to slow the vehicle down until it is travelling safely. Anything else and it applies the brake.

  2. Pcar
    December 19, 2017 at 11:01 pm


    Those laws came into play for me one day on a GPz900R MC.

    Straight road, perpendicular very strong crosswind: had to keep accelerating; then when a hedge broke wind, brake hard; repeat until road changed to more favourable direction.

    Rather testing experience etched in memory.

  3. PJH
    December 20, 2017 at 7:51 pm

    “inertia, which is the force attempting to keep that same railcar stationary”

    LOL. No.

    That’s not what that law says.

    “an object either remains at rest ‹b›or continues to move at a constant velocity, unless acted upon by a force‹/b›”

Comments are closed.