Do you agree with the principles and specification used by HS2 Ltd to underpin its proposals for new high speed rail lines and the route selection process HS2 Ltd undertook? 250 mph is not optimal for rail transport in the UK. Costs are proportional to speed to the power of X, where X is greater than 2. Thus, the costs of travel at 140 mph are more than double those at 100 mph. These extra costs comprise amongst other elements, energy costs, initial costs of equipment specified for the higher speed of operation, wear and tear, and maintenance. Time savings, on the other hand, are less for each increment of speed increase. Thus a journey of 120 miles takes 2 hours at 60 mph, 90 minutes at 80 mph, 72 minutes at 100 mph and 60 minutes at 120 mph, giving successive time savings of 30 minutes, 18 minutes and 12 minutes respectively. For typical UK distances, speeds much higher than 100 mph achieve diminishing returns. Minimising environmental impact by the measures proposed gives rise to ...