It is an unlikely place to forge sporting success but that is just is what is happening deep within the bowels of Sheffield Transport Services’ compound.
Hidden behind the high walls and between buses, lorries and all manner of vehicles is the Steel City ABC, a club that has produced three national champions already this year.
Marshalled by coach Grant Smith, a small, close-knit group of amateur fighters have been making waves since the gym opened its doors in 2002.
But the current crop is the gym’s most successful to date.
Late last month, Sunny Edwards won the senior ABA title - now known as the England Boxing Elite Championship - at 49kg.
Edwards’ crown joined the Youth ABA titles won by Dalton Smith and Chris Luteke in February.
And young junior Junaid Bostan took a step closer to his own national crown by winning the Yorkshire ABA title last weekend.
Such success has fighters banging down the door for a place on the squad.
But coach Smith says keeping the group small is the key to its success.
He said: “I won’t grow the squad and risk not being able to put enough time into every boxer.
“People are asking all the time to come in and train here but I won’t do it.
“I’m not going to give my boxers anything less than what they get now.
“We’re a strong squad and we’re a successful squad.
“This is my strongest squad from top to bottom.”
The close-knit nature of the group is not lost on Edwards - brother of highly rated professional fighter Charlie.
Studying at Sheffield Hallam University, Edwards left behind the reknowned Repton Boys Club to join Steel City.
And he says the close attention helped him win his sixth - and first senior - title.
He said: “I came from Repton and the format is very different. There they have about 70 or 80 carded boxers, all training on the same nights and it’s not a massive place.
“Here, it’s a small squad so you get a lot of one-to-one time.
“For three or four weeks leading up to the the Championships I was in an hour before training for one-on-one sessions and then sparring with the lads after that.
“I had the best preparation I could.”
The junior Smith is the youngest member of the current GB boxing squad and is targeting the 2020 Olympics in Tokyo.
He splits his time between GB training at the English Institute of Sport and his home club and feels that has helped his development.
Smith said: “I’m getting top sparring down there plus the training here that’s got me where I am today.
“I wouldn’t be doing what I’m doing without my dad. The talent he’s helped bring through has been brilliant.”
Arguably Smith senior’s biggest success has ben the transformation of Manor fighter Luteke.
Luteke - whose family moved to the UK from the Congo when he was just two - had never set foot in a boxing gym a little more than two years ago.
But he beat a three time national champion to win his Youth ABA and is on the cusp of earning a year’s contract with England Boxing.
“Grant said I could win it, he believed in me,” Luteke said.
“The kids there had better records and more experience.
“But I pulled it through. I was shocked. I didn’t even smile on my picture because I couldn’t believe it.
“I’m proud of what I’ve achieved and what we’ve all achieved in here.”