how many people do we know that have been in car crashes, for example that say, i don't remember the accident. that's not uncommon. we've been through a traumatic event, the brain wants to protect us by filtering out those bad memories. so that's not uncommon, and i hope that when we do interview him some of that memory will have come back. >> when do you expect to hear from him? to speak with him? today, tomorrow? >> we're not expecting it today, but sooner than later. by the time i meet with the investigator in charge later today i should have an idea of what that timeline is. it's important to give the person time to convalesce. he's been through a traumatic event, and it's also important not to wait too long because memory and perceptions change over time. so we want to do it just as soon as we're able to do it. >> is there any other explanation beyond operator error that could explain how a train could all of a sudden be