The investigators actually placed two mannequins out on the tracks. The train that they were using never actually hit the mannequins, but they did position them in the way that they believe Sheppard and Daniels were standing at exactly 1:53 p.m. last Saturday.
The two mannequins dressed in safety vests and helmets were meant to represent the two BART workers killed Saturday on the tracks in Walnut Creek.
In this NTSB reenactment, each has their backs to the eastbound track, just as investigators believe they did when they were struck.
"The responsibility of safety of their safety is on themselves," said NTSB Investigator-in-Charge Jim Southworth. "The inspector and consultant were required to remain together for the duration of their activity and one of the pair is to be designated as the lookout."
The NTSB has said Chris Sheppard and Larry Daniels had gone out on the tracks Saturday after getting what the BART safety manual calls simple approval. That means as one man works, the other is a spotter, safely off the tracks, constantly looking for an oncoming train.
"When you get a simple approval you are asked and all workers know that you have to provide your own protection, not interfere with main line or yard operations, and you must expect trains on any track at any direction at any time," BART safety trainer Saul Almanza said.
From the NTSB reenactment, it appears neither Sheppard nor Daniels was acting as a lookout.
This reenactment was just part of the NTSB investigation. The rest will be conducted back in Washington D.C.
"The NTSB has taken custody of all image recording equipment on the train," Southworth said.
The NTSB has made a lot of progress in this investigation. They've told us what they've found out thus far, including the fact that the workers had permission to be up there on the tracks at the time of the accident. And that a horn sounded and emergency brakes were applied right before. But they the reenactment is a crucial part of their investigation.
The NTSB says the full investigation could take several months.
The reenactment forced a section of track in the East Bay to be closed from about noon to 4 p.m. Wednesday. There was no train service between the Lafayette and Pleasant Hill stations. That included the Walnut Creek station. BART ran run bus bridges for those passengers.
BART's passengers were feeling a bit frustrated about a shutdown coming right off a strike.
"It's crazy but it's gonna cause a problem for a lot of people," one passenger said.
Another BART rider added, "They shutting down BART again? Give me a break, can I get a break?"