Thee Railway Safety Regulator has alleged that the Passenger Rail Agency of SA stifled its investigation into the April 2015 train crash at Denver station that killed a guard and injured 240 passengers. Prasa officials did not respond to the regulator's requests for information, or provided it late."The majority of the information requested was only provided after the intervention and involvement of [the Railway Safety Regulator] and Prasa CEOs," the watchdog's report states.The report criticised Prasa's system for communicating with train drivers, and for inadequate maintenance and a shortage of critical personnel such as drivers, technicians, and train controllers.The inquiry concluded that "the cause of the collision under review can be attributed to human error on the part of the driver of Business Express train 1602, who was speeding and failed to apply brakes timeously to avoid collision".Mercia Sambo was driving at 91km/h in a 70km/h zone and applied brakes only at about 332m from the point of impact with a stationary Business Express train.The inquiry noted the failure of Prasa to subject the drivers to substance-abuse tests.The regulator's safety report for 2014-2015 paints a bleak picture of rail safety, with R590-million lost to the economy annually due to railway accidents.The number of railway accidents, including people struck by trains, is at its highest in three years, from 4262 incidents in 2012-2013 to 4632 in 2014-2015.Last year, there were 473 railway-related deaths compared to 456 in 2013-2014...