• Question: What do you think could help to give higher-speed trains more balance?

    Asked by Ben Stegs to Natalie on 19 Jun 2016.
    • Photo: Natalie Wride

      Natalie Wride answered on 19 Jun 2016:

      Hi Ben 🙂

      That’s an interesting question. High speed trains are more sensitive to bumps in the ground because of the speed they travel at – it’s a bit like when you’re in a car driving fast over a speed bump – you notice it more than driving slowly over it! Similarly, when the train has to turn, we need to make sure it’s comfortable for people on the train and not making people sick!! This is due to something called centrifugal force and it is really important – if you double (x2) the speed of the train, you quadruple (x4) the force so it can be come really important even for small turns in the track.

      There’s some things in design we can do to make trains balance better. One of these is the spacing between train lines for trains travelling in different directions. When the train travels it pushes the air out the way of it and we don’t want the force of the air pushing out to affect the train on the line next to it. Similarly, we try and make sure the turns in the train lines are small or that big turns are over a long stretch of line so they’re gradual.

      In Japan, they actually have tilting trains which mean the trains can travel around corners without slowing down. These make effects of the centrifugal force less. I’m not sure what year you’re in at school and if you’ve done forces or mechanics at school yet? There’s something called a resultant force which, in this case, is the combination of gravity and this centrifugal force.

      When the train is upright, this force will push you into your seat and to the side (like when you go around a corner fast in your car!) but when the train tilts the force tilts too so it doesn’t affect you in the same way – it feels like a slight pull into your seat which you’re used to when the train travels normally. The same thing happens on an aeroplane when you want to change direction!

      I hope this answers your question! 🙂