The boiler follows GregTech CEu Modern 7.5.3's own source, tick for tick: how fast it heats and cools, the steam it makes at each heat, the water it takes, the four buckets it vents when its tank is full, the explosion when water reaches it after it has boiled dry, how long coal and coke burn, and what a steam macerator draws. Each of those numbers is checked against the mod's code by a script, and the engine's tests hold the rules and show every level can be won. Left out: pipes, since the machines draw straight from the boiler, and the machines' own exhaust vents. The clock runs 15 to 60 times faster than the game.