Going from the reports that Screamscape wrote about....

(6/4/15) Alton Towers theme park remains closed today and says they will stay closed until they determine the cause of the accident on The Smiler on Tuesday. While the latest batch of news articles do not say why the accident happened, a few more details have been uncovered. According to the report on The Telegraph, the park’s management is said to be considering “scrapping” the troubled coaster following the incident. The Smiler has been suffering from some severe issues on both the day of the crash as well as the day before. The coaster had been reported as opening and closing several times throughout the day before the crash took place shortly after 2pm, and was in the process of reopening from one of these shut-downs at the time of the incident, which is why the empty test train was sent out onto the tracks. According to an interview with one of the riders (Vanisha Singh) who was on the second row of the train at the time of the accident, the ill-fated car did indeed get stopped near the top of the first lift hill before the lift was restarted, sending the train down the hill and into the stalled empty train. “We finally went up and were kept at the top for ten or fifteen minutes chatting, joking that we were the guinea pigs. Then we plummeted down and smashed into the test car after doing a couple of loops.” She also described the scene on board the train following the impact as something out of a horror movie, with “blood all over the floor because it was pouring out of their legs in the carriage and dropping down”. The names of two of the four seriously injured passengers were released, a Joe Pugh who is thought to have broken both legs, who was riding next to his new girlfriend, Leah Washington who is said to have far more serious injuries. The other two unnamed passengers were described as an 18 year old girl and a 27 year old man. Unfortunately, the article in The Telegraph also reports that one of the injured is thought to have “lost a leg” due to the accident as well. This is just horrifying to read, and my thoughts and well wishes go out to the riders as well as everyone involved in this tragedy from the park as well. <

Sounds like the accidents maybe similar in cause. It sounds as if the system would not allow the train to drop from the lift as it had either a fault, or the system blocks were not clear indicating a valleyed train. My guess would be that to force the train down the drop the ride would be put into maintenance mode. Typically in an incident like this one would think you would evac the people off the train then figure out what the coaster was doing.