"This is an entirely volunteer organization and activity, so there were a lot of things that were donated, and so that changes kind of the rules of what had to be filed," he said.
Midland is in Texas' oil-rich Permian basin, a region that has experienced a significant oil boom in recent years.
According to its website, Midland-based Smith Industries sells and manufactures oilfield service equipment. The website says the company provides steel and fiberglass tanks, separators, ladders, walkways and other equipment. The company has been in operation since 2000.
Smith Industries has a large facility and warehouse about five miles from the city. On Sunday, the business was closed. An American and Texas flag flew at half-mast and blue ribbons were tied around columns in a small parking lot. Large tanks, pipes, heavy machinery and trucks were scattered behind the gates.
Rosekind said the NTSB will conduct a sight test, probably Tuesday, to try to determine what the train engineer could see leading up to the crash. He said Smith Industries would likely provide a truck for the test.
According to the NTSB, the train sounded its horn nine seconds before the crash. The guardrail hit the truck, and then the engineer pulled the emergency brake, trying to bring the train that was traveling at 62 mph to a screeching halt.
The NTSB based its timeline on cameras and data records.
Killed were Marine Chief Warrant Officer 3 Gary Stouffer, 37; Army Sgt. Maj. Lawrence Boivin, 47; Army Sgt. Joshua Michael, 34; and Army Sgt. Maj. William Lubbers, 43.
Two of the injured were still at a Midland hospital Sunday afternoon, one in critical condition and another in stable condition.
Associated Press writers Ramit Plushnick-Masti in Houston; Danny Robbins in Dallas; Angela K. Brown in Fort Worth, Texas, contributed to this report.