Piling out of the bus at Bo’ness Railway Preservation Site, P7 pupils from Raploch and Buchlyvie primary schools in Stirling have little idea of what to expect from their afternoon outing at Crucial Crew - only that they are going to learn about safety. The big unused railway yard and unmarked Portakabins give nothing away.

After being divided into groups of four, the children take in the Crucial Crew rules: no running; speak only to people wearing yellow badges - those with no badges should be ignored; and, one blast of the horn and it’s time to move to the next “set’’. With a sense of excitement they set off to visit the 11 Portakabins.

Following one eager group across the yard, assistant divisional fire officer Tommy Mann tells the children to run towards an old building. They check his yellow badge and dutifully run on. In front of the building a friendly looking woman beckons to them to come over and go into the building with her. Off they run and pile inside. Their squeals of shock are clearly audible when the door slams behind them and they find themselves trapped in a confined space with only the badgeless woman for company. It takes a scary moment or two for the penny to drop.

Inside, a door opens and the group go into a room where two policemen ask them to account for their actions. Have they not been told never to go off with strangers? Have they not been told not to speak to anyone without a badge? Yes, but... the lady was nice. How did they know that? But there is no time to worry. The horn blasts and off they go to another set.

First introduced in England in the Seventies, Crucial Crew projects now operate all over the UK. Over the past seven years, the Central Scotland scheme alone has involved 8,000 children. Organised jointly by Central Scotland Fire Brigade and Police Force, British Gas Transco, the Scottish Ambulance Service and a number of other national agencies, with funding from local industry, Crucial Crew gives its services free of charge to schools.

The next Portakabin is home from home with comfy sofa and armchairs and a television showing Beethoven 2. Have a seat and relax, they are told. After a check of the man’s yellow badge, they sit down. The smoke filtering under the doorway is barely visible to begin with but quickly envelopes the room in a thick fog. Looks of panic. Are we on fire? What do we do? Once again, pennies begin to drop: fire extinguisher... must get out... phone the fire brigade... shout for help... check everyone’s out... oh no, that girl’s still in there - do we go back and get her?

Safely outside, they are congratulated by the fire officer. He then runs through some of their dodgier responses. Shouting “help” or “fire” once is not enough. “Fire, fire, fire!” is the most effective alert. Remember to give the full address when phoning 999 - the same street names exist in different towns.

Another blast of the horn and off to a different set. Over the railway line - using the bridge, of course - towards the dockside and a new drama.

Someone is shouting for help. They run to the edge of the quay. The tide’s out and 15 feet down in the dense brown sludge of the Forth, a young man is stuck. The children look around. There’s a step ladder down the harbour wall - too dangerous, they decide. There’s a lifebelt. Stop and think - could they take the man’s weight, complete with mud coating? There’s a phone - that’s the best idea. Members of the Police Underwater Squad praise the children’s sensible approach.

Although they’re now prepared for the unexpected, the apparently innocuous nature of each set catches them out every time. At the electrical sub-station, complete with standard “Keep out. Danger of Death” notice, the yellow-badged Scottish Power officer pleads with the group to retrieve a ball from inside. He’s very persuasive: “Why not use this stick? Oh, go on, it’s my wee brother’s - he’s dead upset.’’ One boy decides to do the honourable thing, pokes the stick in - CRACK! The group leaps a foot in the air, the boy blanches and counts his lucky stars that the full force of the station had not zapped him to a frazzle.

And so it goes on. In a messy gang-hut children are asked to spot anything that might worry them among the mess. They quickly spot three disused syringes and are unanimous in their decision not to touch them. The Drug Squad officer in charge praises their foresight and emphasises the importance of “guarding’’ their find to protect others, while seeking help.

On the Transco set, after having learned to recognise the smell of gas from a scratch and sniff card, gas smells builds up in the room and immediate action is needed. The children extinguish candles, turn off the gas fire and cooker but switch off the light. BANG! Another terrified leap in the air. Another lesson learned.

At their final de-briefing session, fire officer Tommy Mann says: “The kids are here to make mistakes. There are terrible consequences if they make them in real life. It’s virtually impossible to quantify the success of Crucial Crew.”

Indeed, earlier this month an 11-year-old girl who had taken part in a Crucial Crew safety event came to the aid of her classmate who had fallen 40ft down a rocky gorge wall. Stephanie Butler of Todsmill, Upper Kinneill, scrambled down to her friend, Mhairi Waddell, and, recalling her training, tried to put her in the recovery position, before climbing back up and racing home to raise the alarm. “We’d been at the Crucial Crew safety event at the railway station,” said Stephanie, “and I remembered our lessons.”

Central Scotland Crucial Crew, tel: 01324 716996. Crucial Crew schemes operating in Tayside, Strathclyde and Lothian and Borders can be contacted through local police force community services.