The yellow jackets march from the Brisbane Street Mall, up George Street, down York Street, up Charles Street, down Paterson Street, and back to a parked coffee cart, where three other stationed volunteers will take over.

Outside a popular venue a middle-aged woman is crying. The three women in the yellow jackets pause, but they are assured a taxi is on its way, and they don't pry.

A man with white-chapped lips sways towards them. Would he like a lolly? No thank you. What about some water? Um, yes, actually. He sways off.

The words, "Can I have a lollipop?" suddenly ring through the air. They are coming from a car parked at the lights. The questioner is obligingly passed a lollipop through the window, plus one for his girlfriend, and the tyres screech as he drives away.

The three yellow-jacketed women are part of the Salvation Army Street Team, and they are shivering through this cold snap of a spring night to make sure everybody out gets home safely.

In 2012, an 18-year-old boy named Thomas Kelly was killed in a random one-punch attack while walking at night in Kings Cross, Sydney. Two years later, the organisation founded in his name began a program.

The idea behind the initiative, which was originally called Take Kare, was to send trained, non-judgmental volunteers into streets that have a high volume of partying young people at night. The volunteers aren't the police, but they are sober adults who can keep an eye on things - armed with water bottles, conversation-starters in the form of lollipops, and other useful goodies. From 2014 onwards, the teams began stationing themselves in capital cities. About three years ago, the program arrived in Launceston as the Salvation Army Street Team. On this particular Saturday, they invited me to join them.

The Street Team is made up of about 20 volunteers who take it in turns to head out every second Saturday. Tonight, the crew of six is anchored by the Reeves: Anita Reeve, the social operations manager of the Salvos Launceston; Warren Reeve, manning the coffee machine; and Lilly Reeve, only 17, and a recent addition to the volunteer team. The Reeves are immediately likeable people; non-judgemental, practical and irrepressibly cheerful. At about 11pm, I walk to the parked Street Team coffee cart to join them for the evening.

I feel uneasy walking alone from my Cimitiere Street office to the St John Street end of the Brisbane Street Mall, where the cart is parked. It's not even midnight but already Launceston's bars and clubs are doing a brisk trade. Indistinguishable shouts echo along the roads, and I avoid eye contact with the boisterous groups of young people I pass on the way.

Before I found the team, I was worried that not enough would happen for me to write an article about. And anyway, I had the idea that heavily intoxicated people would feel uncomfortable around hi-vis-wearing, sober representatives of the Salvation Army.

But as it turns out, the complete opposite is the case. Just about everyone who passes by the cart wants to give the team a a slurred, lengthy rendition of their life story. The volunteers listen patiently, and suggest support services if the individual seems like they might be in trouble. From 11pm to 1am, they are kept so busy that I barely have time to interview them.

By the time I arrive the volunteers have already set up: the coffee machine is hissing, the picnic table has been assembled, and the tub is full of biscuits.

The next step is for three of the volunteers to set out on a patrol. The one I join consists of Anita Reeve, a woman with a brown bob named Alison Bates, and a woman with a blonde bob named Sue Wynne.

Alison Bates explains that she has children that are nearing Saturday-night-clubbing age. It comforts her to think that there might be people out there helping her kids, she says - if they needed it. And within half a block, the three yellow-jacketed women have helped two strangers.

Immediately after crossing the St John Street intersection they encounter a beautiful girl in a beautiful olive-green dress. She is crouched in the gutter, shoulders bare even though it is four degrees, clutching her stomach. The volunteers help her across the road to the coffee cart. It quickly becomes apparent that one of the most important functions of the cart is that it is a safe, well-lit, supervised place to wait: for a taxi, for friends, for your stomach to stop churning. So the teary, sick girl is deposited there to buck up, and the patrol carries on.

Next, the trio are approached by a group of boys who want to know if the volunteers have a bandaid: the problem is that one of them is bleeding from the head. I wouldn't put money on them being old enough to drink, but they are exceedingly polite. "Thank you so much for this, we really appreciate it," one of them half-shouts in the way that drunk teenage boys communicate all information. "You're doing such a good thing." They stagger off with their bottles of water, narrowly avoiding a pulpy smear of vomit on the footpath. The one who had fallen over has a bandaid freshly plastered on his forehead.

And so it continues.

Back at the cart, the volunteers are at the centre of a hub of activity.

One of the most surprising things about the evening is the amount of children hanging around; the demographic now nursing hot chocolates and sucking on lollipops. Not just young people, but actual children. There must be at least ten people between the ages of about nine and 14 milling about, after midnight on a Saturday night, filling in time.

As well as dispelling waters and band-aids, the volunteers are also there to be the "eyes and ears", as Anita says, of emergency services. They often encounter people in various states of alcohol poisoning, either semi-conscious or completely unconscious, and people that are in, or are causing, some sort of danger.

Tonight, a girl has run away from home. I would guess by looking at her she is about 13, though I have no concrete idea. The girl is refusing to go quietly with the adults who are attempting to get her into a taxi. She slithers out of her clothes when the adults try to grab her, and she runs off into the night wearing only her underwear.

The volunteers are wearing looks of intense consternation. But this is out of their remit, one of them tells me. They debate whether or not to call the police, and don't take it personally when they are sworn at as the incident unfolds. Later, I see the police out in their comforting blue-and-yellow uniforms, helping search for the runaway girl.

Meanwhile, at the cart, a man is playing Dire Straits on his phone and dancing by himself. Two girls come barreling towards us at a sprint, clattering in their heels, yelling "I want a hot chocolate". Behind us, tuneless singing has been coming from the centre of the mall for a couple of hours - a regular occurrence, I am informed. There are many rounds of hugs. Unsolicited hugs from strangers are clearly a major occupational hazard for the volunteers.

The team provide a number of services that make the heart swell with vicarious gratitude, along with the water bottles and the biscuits. They pick up glass. They take cups of coffee to bouncers. They offer sick bags for those who are too nauseous to otherwise risk a moving vehicle. And they distribute thongs, for the women who are walking around carrying their high heels.

I have never been out on a Saturday night at 1am in a state of complete sobriety before. It feels like an anthropological exercise. And it's mostly a heart-warming one: due to the party-goers, propelled through the streets in a mad rush of uninhibited energy, dressed up and disheveled; and from the volunteers, sacrificing their nights to ensure they are doing so safely.

As Warren Reeve observes just before I depart, it's a time to observe the kaleidoscope of life in all its colours.