what happens next caught on surveillance camera from a nearby building. watch as sparks fly as over 100 miles an hour. the deadly speed catapulting seven train cars and the engine off the tracks. >> we will have positive train control on the northeast corridor section by december 31st. >> reporter: amtrak's ceo says that safety mechanism to prevent human error will be in place by the congressional mandate. but some say too little too late. why isn't it done now? was it an issue of cost? has it just come down to the bottom line? >> no it's a time issue and also a cost issue. >> reporter: all right. back out here live this morning cnn has also learned an automatic braking system has been in place for years on the opposite side of the tracks to slow trains going southbound trains from new york to d.c. as it enters that curve. however, that slowing mechanism is not on the side of the tracks where this accident happened.