The Steelworks is located on the Mainland.
Both the steelworks' precise location and years of operation is unknown.
Hurricane, a large tank engine, and Frankie, the diesel shunter, were the only permanent resident and workers of this massive industry. Their duties include emptying slag, arranging trucks and making deliveries, presumably often to Bridlington, as Hurricane said, "I deliver goods there all the time!"
It could be assumed from Frankie saying "Thomas is my favourite new engine." that the two of them force visitors to stay and work with them on a regular basis (presumably via singing the welcoming song "The Hottest Place in Town"). No matter how many of them were captured, however, they all seem to have managed to escape.
The most recent skirmish of the Steelworks occurred after the arrival of Thomas, who trespassed into the steelworks by mistake as he was lost on his way to Bridlington Goods Yard. After persuading the unknowing tank engine into leaving his trucks, Hurricane and Frankie performed the welcoming song. That, plus Hurricane informing Thomas that he delivered his trucks during the night, were enough to convince Thomas into working hard at the steelworks all day.
However, after Hurricane and Frankie left on a delivery, a homesick Thomas attempted to escape via a track leading into the woods. This resulted in his own derailment, and a reprimand from Frankie once she and Hurricane returned and rescued the tank engine.
That didn't stop Thomas from making further escaping plans. When Hurricane and Frankie were fast asleep, Thomas tried pushing the steelworks gates. When that failed, he found some flatbeds loaded with pipes and rails for his aid in crashing open the gates. This woke Hurricane and Frankie, but by the time the two of them set chase, Thomas had already succeeded in bashing himself free. After a brief chase, the two steelworks engines gave up the search, because Thomas had turned off the main line and hid in a siding.
Later that morning, Hurricane went to Bridlington again, where he heard James inquiring about the whereabouts of Thomas and info about himself. Somehow, he managed to lure James back to the steelworks, where they performed their welcome, but were stopped abruptly by James demanding on revealing where Thomas is. The two originally tried to play dumb on Thomas' name, but after realising James knew about Hurricane delivering his trucks, Frankie made up that Thomas would return soon, and forced James into working while waiting for him.
Unbeknowest to either James or the steelworks duo, Thomas had brought experimental engines Lexi, Theo and Merlin to assist in James' rescue. Lexi and Theo crashed some engine parts on the line, successfully diverting Hurricane and Frankie out to inspect and "help". All seemed to be going according to plan, until Merlin decided to give up his keep-watch post and sneak in to the steelworks after Thomas, using his supposed invisibility ability. Both Lexi and Frankie saw him, with the latter quickly reversing back in with Hurricane, and thus a chase broke out between Hurricane, Frankie, Thomas, James and the experimentals.
The chase ended when Hurricane pushed Thomas out of the way of overturned molten slag, resulting in his own wheels being melted and damaged. Frankie was utterly depressed at the idea of carrying out all the heavy work on her own, also explaining that their actions were only for recruiting some help for themselves. Thomas suggested that the experimental engines stay and provide just what the steelworks engines are after - assistance. They did, in the end, with the steelworks now having a fleet of five engines in service.
The steelworks covers a massive area. From entering the gate, there is a yard with many sidings and crosses, including a turntable and a shed that is open at both ends. There are at least two entrances into the building, and a two-track shed for Hurricane and Frankie to occupy at night. Two gantry magnets were seen, the route of both them, it seems, are designed to travel to and drop things into the big melting stove.
Perhaps the most complicated system in the steelworks is the slag system: a chute opens up to allow slag to slide down along a path, before splitting into three branches, parted at exactly the distance the ladle trucks used to transfer them, are. Some slag appears to travel on another way: being loaded into rectangular molds. It is unsure what use these slag are being put to for this. After these two slag processors, a conveyor belt appears to transport pipes, from where it's unknown.
The steelworks' engines' main job is to transfer these slag onto the Slag Heap Embankment at the back of the building, from which workmen pull the lever on the trucks to empty the slag into the slag heap. A track branches off from the one that heads up to the slag heap embankment, one which Hurricane states, "Hasn't been used for years!", and one which is not yet known where it leads.