dr. todd curtis, dr. curtis are you there? >> i can hear you. >> while we are speaking the govenor has arrived on the scene as well as police commissioner ray kelly. so, dollar dr. curtis to be cles very, very early on this very lengthy investigation. as you have been listening this morning the early witness accounts the train was going fast. the trains go fast. do we really know what that means right now? >> we don't. because how fast the train should be going in that particular section of the track will depend on several factors. and one of the factors that was mentioned a few minutes ago was the fact that the train was being not pull by a lyco mow l , it was pushed by a locomotive. it te depends on the procedure f the rail company. >> tell us what is different if it was pushed by a will h a loce rather than pulled. this has been a train that has been up-for-quite up for quites they have specific pro see procs for what kind of locomotion should be done for this kind of situation. given the passenger load and the number of ca