Ready Meal.

There are 4 microwaves to trigger:

#1 Main hall in Yaughton. Just as you enter, turn right.
#2 Second building on the left as you enter Yaughton. There's a sign in front of it reading "Sheperd's Walk"
#3 Howard's house. In the last area of the game. He's the manager for the train yard so look for his coat as you enter the house.
#4 Stephen's house which is in Tipworth

Click to trigger. You'll hear a ding from each one.