Gravity Train-A New Rumour

There is a new rumour going on that scientists may be working on the gravity train concept. In the past famous scientists like Robert moon in 17th century and Isaac Newton in 19th Century have already given this concept of an object moving inside the planet not only that, this idea took more attention of scientists when it was published in the American Journal of Physics in 1960s. According to this concept all straight-line gravity trains will take the same amount of time to complete their journey from one side to the other and for earth this time equals to 2530.30 seconds which is equal to 42.2 minutes for each journey.
The maximum speed is reached at the mid point of the trajectory and for earth the maximum speed is 7900 m/s which is equal to 28440 km/h. Now for the information let me tell you that one of the world's fastest or probably the world's fastest aircraft the north American x-15 has record speed of 7274 km/h which is well behind the gravity train's expected speed, the question is whether it is possible to control the speed of this train because as far as my knowledge goes a normal human body cannot travel at such speed. The other thing is the heat of plasma and the earthquake situation which can be really dangerous. The scientists may control its speed by the use of magnetic friction but the real question is the heat of plasma and the earthquake situation and this is the question which needs to be answered.