The major premise of the movie is precisely how it happened in real life. The bus was stopped in that manner; and the driver and children were buried in a container within the grounds of a quarry.
However, the fine detail did leave a lot that was sacrificed for artistic license and narrative flow.
The first casualty was the time scale. In reality, Woods and the Schoenfeld brothers took between 9 and 18 months to plan 'the perfect crime'. In the movie, this is contracted into a matter of weeks, making it all appear much more impulsive. The speed helped make Rick Schoenfeld seem like an innocent caught up in events, and as much a victim as those in the container.
As viewers, we were asked to focus upon Ed and Tim. Therefore they were the ones who facilitated the escape of the children. While Ed was hailed as a hero upon their escape, he doesn't seem to have been so stoical in reality as in the movie.
The children told how, as soon as they heard the soil being shoveled over their roof, Ed commented that they were 'goners'. While he undoubtedly did a lot of the heavy lifting, which ensured their escape, it was largely the older teenagers who kept up morale.
I do not wish to undermine Ed Ray's character in any way here. By all reports, he was a hero. He did lead those children to safety. But I think that the movie afforded him some of the glory, which should rightly have gone to his charges.
For example, it was not Ed who reached up into the cavity above and found the batteries weighing down the hatch. That was two boys, aged 14 and 10, who inched it towards themselves. This was done in stifling heat, which had already seen another boy faint. The children worked for hours in it. They managed to hand the batteries down to Ed, who was standing on the floor.
Tim did not exist in reality. He appears to represent a handful of older children, who really were amazingly resourceful in that place. In all, about five of them worked in that hatch, leading to their eventual escape.
That was also slightly altered in the movie. In reality, a fourteen year old boy sneaked out and hid in bushes, fearful of being shot. Then he dashed back to the hold and reported his survival. Ed handed the children up to him one by one. They each scampered into the bushes and cowered for safety.
Once all were out, Ed hunted down the quarry's patrol guards, who had no idea that they had been there. That is how the alarm was raised. In the movie, the whole party stagger through the nearby roads, in the middle of the night, until a passing motorist is flagged down.