FOR more than a century, coloured levers were manually pulled to direct trains at Hamilton Junction, a switch was flicked to lower the boom gates, and globes lit up on a map to show where carriages were.
It is an intricate system that is still working perfectly more than 125 years later - it is just connected to a computer and a miniature railway model.
Inside the Hamilton signal box, where the railway line crosses Beaumont Street, history lives on.
Signalling manager Ben Armstrong said the site is now used as a training facility and an educational display.
"We've put in a simulation that means the signal box functions as it used to, but without being connected to the live infrastructure," he said.
"The frame itself is still in original condition."
The mechanical interlocking system is linked to the model railway inside the restored signal box - featuring the station, the boom gates, the railway lines, and a train - via a computer system.
"So you can come here and move the levers around and points will move, signals will clear, everything was functioning as it used to," Mr Armstrong said.
"It's important to be preserved."
Mr Armstrong said Newcastle looked very different back 1898 when the signal box was first opened, with four tracks at the Hamilton junction and the Beaumont Street crossing being the main one for coal trains.
He hasn't been around quite that long but Mr Armstrong said he does have a long passion for his line of work.
"I've had almost a lifetime of interest in trains and I've been involved in heritage railways for nearly 30 years," he said.
"You know what they say, if you work in your hobby, you never really work a day in your life."
He said his favourite part of the restored signal box was the indication system - the original map with lights that showed where a train was along the track.
"It just shows a lot of history," he said.
Heat stains from the globes lighting up across the decades are still visible.
"People love coming up here - there's obviously the heritage building itself, it's close to an operational railway ... it's also rare to get an opportunity to play with a signal box," he said.
Sydney Trains chief executive Matt Longland took a tour of the signal box with other guests, including Transport for NSW secretary Howard Collins, as part of Rail Safety Week.
"We're reminding all the community to please take care around trains, expect the unexpected around rail network," he said.
"Please be careful, we see far too many incidents every year where accidents do happen.
"It's terrible for the people involved and their families, also very difficult for our staff that work on the network."
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