Colwyn Baker - of Edinburgh - along with David Hennessy and Nigel Putman are said to have preyed on youngsters at the now-defunct Swaylands School in Penshurst, Kent, from 1963 to 1993.
As well as the abuse allegedly committed by the trio, jurors were also told that Baker also allegedly encouraged other pupils to commit sex acts on other children.
The men were residential child care officers at Swaylands School, which closed in 1993 after catering for boys with emotional and behavioural difficulties.
The trio face a total of 49 charges against 24 victims, some aged around 10 to 15 at the time the abuse was said to have occurred at the school.
At Maidstone Crown Court, prosecutor Philip Bennetts QC told the jury that the atmosphere at the school at the time “was one where abuse was almost the norm”.
One of Baker’s alleged victims became so scared that he often stayed awake at night, sleeping in stairwells to avoid Baker, Mr Bennetts said.
As a result, the boy would often fall asleep in class, causing a dramatic decline in his learning. But Mr Bennetts said the boy ended up being caned by the headmaster as punishment for dozing off.
The court heard another boy disclosed how Baker would wake him in the middle of the night and abuse him almost nightly for three years.
Another boy told investigators that Baker was in charge of the Scouts, karate and swimming, adding: “Anything good that you wanted to do as a boy, Baker was in charge of it.”
Baker, 71, of Craighouse Avenue, Morningside, faces 24 counts of indecent assault and three charges of buggery.
Hennessy, 74, of Norfolk, has been charged with 17 counts of indecent assault, one of gross indecency with a child and one of buggery.
Putman, 62, of Berkshire, faces three charges of indecent assault.
They deny the charges against them.