Special edition of the engineering challenge, celebrating the 200th anniversary of Richard Trevithick's invention of the steam locomotive. Three teams have 20 hours and the materials they manage to scavenge from the scrapheap to build steam, diesel and electric-powered versions capable of pulling a 20-tonne passenger carriage, before putting their creations to the test in a face-off between the golden age of rail travel and its modern-day equivalent.

A look back at the series' best bits of bodging, as Robert Llewellyn and Lisa Rogers present 'The Rusties': Scrapheap Challenge's very own awards

Grand final.

The Challenge The Thirsty Knights of Norfolk and the Belfast boys Hairy Hogs go head to head as two teams of bikers battle it out in a race across a lake in their scrappy craft. They must rescue their stranded expert before returning safely to dry land and, hopefully, a place in the final. Hairy Hogs The Hairy Hogs sailed into the semi-finals by scoring a victory over the tree-hugging recyclers The Hogs are three fun-loving bikers from Belfast. Captain Conn Kelly, Darrell Hanna and Alastair Nethercott combine the talents of an electrician, mechanic and a plumber and are all members of the same Harley Owners Group. Big men, with personalities and hearty laughs to match, they are up for most things – except water-based challenges. So having come through the Jet Boats challenge, they'll be hoping for terra firma this time. Ha! Helping them is Simeon Oakley, a freelance designer/fabricator who has built a wide range of marine vessels, from boats to hovercrafts. Born in Woomera, Australia, on a rocket range in the desert, Sim grew up in Saudi Arabia on an RAF base and went to school in North Wales. He has worked for a circus, designs and builds interactive exhibitions for science museums and lives on a restored Thames barge. He's a great engineer, he's a very cool customer and he's quietly confident. The Thirsty Knights The last time we saw The Thirsty Knights, they were gliding past Honda head-honchos The Fireblades in their flying car. Captain Pete Twissell, a design engineer, his brother Frog (yes, that's his real name) Twissell, who is a Buddhist and a vegan, and welder Carl (Roo) Verlander are The Thirsty Knights. This team is quirky, alternative and very intelligent. Yet another team who love their bikes, they have owned, built, raced and maintained many over the years. Used to thinking laterally to get around a problem – they love designing the weird and wonderful. What they produce will be a creation in every sense. Joining them for this boating battle is Bill Rutland, an East-End boat-builder and engineer who has spent all his life working and living on the docks around Tilbury. Bill's firm, SEMEC Engineering Ltd, undertakes a variety of jobs from maintaining boats and barges to engineering specialist pumps for Thames Water. Bill is even building his boat from scratch as a hobby. So far, the 48-tonne craft has taken three years. His practical skills, engineering nous and years of expertise make him an ideal expert. The judge This week's judge is Commander Steve Farrington who has spent a lifetime in the Royal Navy as a marine engineer and is an expert in amphibious ships and landing craft. Currently with the Royal College of Defence Studies, he has been posted to many ships, including the aircraft carrier HMS Hermes, the assault ships HMS Intrepid and HMS Fearless. With that experience, he is the perfect person to preside over this challenge.

The Challenge Spy Cars The last quarter-final mission, should our challengers choose to accept it, is to build a stealthy 'spy car' for use on a secretive information-gathering exercise. Their reconnaissance vehicle will have to carry the entire team both under and over obstacles which are just two feet from the floor, turn on a sixpence and then back out of trouble. They must avoid detection whilst infiltrating a sinister-looking base protected by guard posts, razor wire, security cameras, alarms and laser beams. Once inside, they must limbo, hurdle, twist and turn their way into (and out of) danger in order to steal a top-secret briefcase before making good their escape. Bakewell Puddings The last time we saw the Bakewell Puddings, they were pitting their wits against Rough Riders, three North Sea gas engineers from Hull, in Off Road Rescue. Nick Marriott, Mark Elliott (Smell) and his nephew Andrew Charlesworth (Charlie) are from Bakewell in Derbyshire. All are into bikes and racing (Motor Cross and Enduro). Mark and Nick have been friends for 20 years and have been in the same Motor Cross team as well as in a punk band together. Mark started to teach Charlie to ride at the age of nine, so it's fair to say bikes are this team's thing. Mark is an engineer, Nick is an architect and Andrew is a Rolls Royce engine inspector. These guys are also outdoorsy, sporty, rugby-loving, mountain-climbing kind of people who participate in the annual Bakewell raft race and the odd cross-town wheelbarrow race. They thrive on a challenge and have plenty of ingenuity and humour to keep us all entertained! John Ricketts (also known as Johnny Nitro) is a drag racer of the classical style à la American Graffiti. He owns, maintains and races his 8-litre 1965 Chevy and has been known to fit a nitrous oxide system to a Ford Anglia. When he's not being a petrolhead, John can be found catching tubes (that's surfing to you and me) off the Cornish coast. Up 'n Atoms Up 'n Atoms reached the quarter finals by bowling over the REME Rebels, three female soldiers from the Royal Electrical and Mechanical Engineers, in Bowling Bangers. Ali Day, David McFarlane and Jimmy Ridewood are expats living the life of Riley in Geneva. They work at CERN (Europe's largest centre for nuclear research) and explain their work as Star Trek-type stuff, experimenting with smashing particles together to see what happens. They're science boffins but not in the slightest bit geeky. They enjoy playing on the slopes of Switzerland, rugby, British sports cars and a good pint or 14. They have a background in off-shore work and have nuclear power station training – so there is an extremely solid engineering skills base here. They claim that James is the 'looks' of the team, Ali is the 'brawn' and David is the 'brains'. Up 'n Atoms' expert is Jim Chalmers, a creator of whacky vehicles. By day he runs a large workshop outside London but he's happiest when he's inventing – most recently he patented what could be the world's smallest commercial hovercraft. He's recently got in trouble with the police for strapping a jet engine to the top of an Escort. Future projects include building a McLaren F1 – for the road! The judge John Hetherington is a veteran of Scrapheap after judging the Minesweeper challenge back in series 4. John is a professor of engineering design at Cranfield University and head of the Engineering Systems Department at the Royal Military College of Science – he's the man who teaches potential Qs!

The Challenge Power Rowers Scrapheap goes back to the water for the latest challenge as The Anoraks take on Maximus. In honour of our Olympic oarsmen and women, the two teams have to assemble a mechanised galley with at least four oars to scull their way around our tricky aquatic course. The Anoraks The Anoraks In this year's first episode, The Anoraks poured cold water on The Hoselliers, a team of fire fighters from Blackburn, as they raced out of our sheer sand trap in Surrey. Deprived of their captain Geoff Turtell for their second challenge, The Anoraks are now led by Marc Draper. Lyndon Camidge joins him again along with Andy Cross an old school friend of Lyndon's who comes in as a substitute. Andy is a plant fitter and HGV mechanics expert. Named after their club of the same name, these three enthusiasts from Surrey can't get enough of off-roading. The lads spend their spare time in Marc's garage, building and restoring Land Rovers and other 4x4 vehicles. Lyndon claims he has broken, crashed and sunk more Land Rovers than he's had hot dinners and Marc likes to think he is the stabilising influence of the team. Lots of experience, slightly batty and a bit posh, these boys are determined to go all the way! Rob Austin is The Anoraks' expert this week. He's an engineer and teacher from Oxford who organises the Formula Schools engineering challenge. Rob worked as a professional fabricator and engineer in various fields before going into education and creating a successful engineering course for schools. He now runs Formula Schools, a scheme to get youngsters interested in automotive and maritime engineering. From his well-equipped workshop in Oxfordshire, he builds and fabricates pretty much anything and is currently rebuilding a classic Bugatti racing car. Top Maximus Maximus Our second set of challengers are the rickshaw-riding charioteers Maximus, who bowled over Irn Cru in the fourth challenge of series seven with their barmy bouncing bomb. Cycles and big barges float these Bath-based boys' boats. William Trickett, Paul McGarry and Dennis Mapp work at Cycles Maximus, which makes and supplies rickshaws. William, or Trickett as he likes to be known, is also a boat engineer and has a company which makes luxury Dutch barges. They are into all kinds of cycled contraptions from rickshaws and chariots to trikes and motorbikes. They also share an interest in canal boats – so are used to building things out of the ordinary. They are quirky, alternative, great fun and are phased by very little. Trickett is completely mad, Paul lives on a canal boat and is also a circus performer and Dennis is a Motor Cross rider who, in his own words, will have a go at anything! A great team. Maximus' expert Jim Bond is not an engineer but an expert fabricator and metal-work sculptor. His speciality is mechanised sculptures. He has worked on TV series like The Secret Life of Machines and can easily grasp the concepts behind automating a human movement mechanically. Cool and calm, Jim is used to getting kids motivated about engineering projects but confesses he is a bit laid-back. The judge The judge Richard Carless is a keen rower and has lived and worked on the water all his life. He owns a marine safety business for the film industry and recently worked on the BBC's Building the Impossible: Submarine episode. He is a Guinness Book of Records holder for several rowing endurance and distance records. He recently smashed the long-distance rowing record from the origin of the Thames to the Thames estuary. He knows what it takes to make a good rowing stroke and being a boatman all his life can tie this into both engineering and hull design.

The Challenge This week our teams will have to earn their Scrapheap wings! Norfolk bikers, The Thirsty Knights, and Honda head honchos, The Fireblades, won't actually be leaving terra firma but they will be challenged to build cars that are powered and steered by a propeller! The Fireblades Steve Martindale (Smarty), Chris Barfe (Barfy) and George Wise (Big George) have known and drunk with each other for 10-15 years and work in different divisions at Honda UK. They have a broad span of interests ranging from motorcycle racing, classic cars and Raleigh Choppers to singing rock 'n' roll, Chelsea FC and running marathons! They are confident that between them there is not an engine around that they haven't worked on. These boys like power and speed and as long as it's fast, they don't care what they build! The Fireblades' expert is John Gifford, a Scrapheap veteran who appeared in series 5's Hovercraft. He is one of the UK's foremost hovercraft designers. He built his first hovercraft at the age of 16 and recently appeared in a Bond film as a hovercraft stunt driver. His firm, Griffon Hovercraft, builds vessels for coastguards and the military. The Thirsty Knights Frog Twissell, (yes, that's his real name) Pete Twissell and Carl Verlander (Roo) combine to bring you The Thirsty Knights. Frog is a paragliding Buddhist vegan who likes to play with fire, Pete is a pagan who says he has an empathy with machinery and is to nuts, cogs and engines what Dr Dolittle is to animals and Roo is a welder extraordinaire who claims he can tap dance whilst playing the flute! This team are quirky, alternative and very intelligent. Yet another team who love their bikes, they have owned, built, raced and maintained many over the years. Used to thinking laterally around a problem, they love designing the weird-and-wonderful. Their machine will be a creation in every sense of the word! Billy Brooks is The Thirsty Knights' expert and he's a mad inventor and microlight-flying maniac. Billy is also a Scrapheap veteran, appearing in series 2's Flying Machines as well as Scrapheap's US equivalent Junkyard Wars. His day job is as a microlight designer but by night he can be found living on his barge. The judge Judge Brendan O'Brien holds the world record for holding the most world records in aviation. His day job is a stunt flyer – you don't need a hobby with that on your CV. One of Brendan's future projects includes crossing Greenland on a propeller-powered microlight sled. As you do …

The Challenge This week's challenge is to build jet-powered speed boats that are both agile and fast. The teams will be competing in a two-part Grand Prix – on jet boats! The race will start with a full-throttle dash up and down the lake and will be followed by the twists and turns of an off-shore obstacle course. Hairy Hogs Conn Kelly, Darrell Hanna and Alastair Nethercott are the Hairy Hogs from Northern Ireland. All members of the Provincewide Harley Owners Group, they are big blokes with bigger laughs who love their Harleys and spend much of their year touring around Europe on them. The Hogs are seriously hands-on and have had experience of most possible mechanical projects. They are rough 'n ready, rugby-playing, Guinness-loving men who are up for the challenge and in search of a 'good craic'. These guys are quietly confident they can't be beaten and should give even the most solid of Scrapheap teams a run for their money! Apparently, they're up for most things apart from a water challenge (ha!). Alan Pickard is the Hairy Hogs' expert as well as being one of the foremost jetskiers in the UK. He runs Jet Shed, the leading specialist workshop in this field in the UK. Previously seen on White Water Rider (series 4), he is a hands-on bodger and technician and previously held the speed record on a jetski – he is currently ranked number three in the UK. Team Ragbo Glynn Myers, Nick Mellor and Colin Bates all work at Smart Recycling, Glynn's plastics waste-recycling firm in Lancashire. Between them, they have worked on everything from factory equipment and heavy plant machinery to cars and bikes. This team are heavily into their bikes and two years ago Nick sold his house so he could buy a Triumph bike – he now lives in a caravan! There is a wide breadth of experience and knowledge in this team and the guys are confident they can deal with anything we throw at them! Glynn and Colin are larger than life in every respect, with 'Hippy Nicky' being slightly quieter – but he sees himself as their 'secret backbone'. Lots of northern humour, loads of energy and bags of banter – you won't be able to get a word in edgeways! Alex Wallis is Chief Engineer at Pursuit Dynamics and will be Team Ragbo's expert this week. His company specialises in pumps, fluid management and innovative marine propulsion systems using steam power. Alex is a mechanical engineer with a practical background, particularly in the bodging of various automotive matters and he's even built his own sail plane. The judge Michael McDowell works for Polaris UK as their technical man, on hand to answer any mechanical problems in the Polaris Jetski dealership chain. He also trains all sales outlets on the mechanical running and maintenance of Polaris Jetskis. He has been working for eight years in the field of maritime power units, impellers and jetskis. He also has an engineering background in motor mechanics, quad bikes, outboards and even pumps. When it comes to summarising what makes a good jetski, Michael can talk at length about all the key ingredients with consummate ease.

The Challenge This week's challenge is to build off-road rescue machines capable of lifting a hampered hatchback from a water hazard before carrying it cross-country to the safety of stable ground. With steep slopes to get up and down, sticky bogs to get stuck in and soft, slippery sand to sink into, our teams will operating at the limit of their bodging capabilities. Rough Riders Ozzie Senior, Barry Eastaugh (Bazza) and Jason Lord are three Yorkshiremen who spend half of their lives 20 miles off the coast of Hull on a gas storage platform in the North Sea. Between them, they oversee and run the safety, maintenance and mechanical upkeep of the platform. They have a wealth of mechanical engineering experience ranging from heavy plant machinery to bike and car engines. Barry is a 'guru' of a welder and there's not a lot these boys have not had a go at. The Riders have big characters and enthusiasm to match. Ozzie is a karaoke king and has won many an Elvis impersonator competition (and he is also likely to burst into a song at any given moment). Barry is known for his year-round tan and Lycra shorts. The Rough Riders are guaranteed to rise to any challenge – and they'll probably do it singing! The Rough Riders' expert is Tim Dray. He started out as an agricultural engineer and soon fell in love with off-roading. He has built many an off-road vehicle and has spent a lot of time organising the Camel trophy. Since this period, he has been a consultant to Land Rover, building and designing their 4x4 courses. Bakewell Puddings Nick Marriott, Mark Elliott (Smell) and his nephew Andrew Charlesworth (Charlie) are from the Derbyshire town of Bakewell. All are into bikes and racing (Motor Cross and Enduro). Mark and Nick have been friends for 20 years and have been in the same Motor Cross team as well as in a punk band together. Mark started to teach Charlie to ride at the age of nine, so it's fair to say bikes are this team's thing. Mark Elliott is an engineer, Nick Marriott is an architect and Andrew Charlesworth is a Rolls Royce engine inspector. These guys are also outdoorsy, sporty, rugby-loving, mountain-climbing kind of people who participate in the annual Bakewell raft race and the odd cross-town wheelbarrow race. They thrive on a challenge with plenty of ingenuity and humour to keep us all entertained! The Bakewell Puddings' expert is Steve Matthews and he's been building commercial recovery vehicles for the past 20 years – mostly out of scrap! In the past, he's also renovated tanks. He doesn't like beer, so what does he do to relax? Well, he likes nothing better than a cup of tea and ... building more cars! The judge This week's judge is Simon Buck, the only British winner of the most hardcore of all 4x4 events – the Malaysian Rainforest Challenge. His motto is 'it's better to be a spectacular failure than a dismal success.' He's a gung-ho guy – enough to drive at 70mph through the Malaysian rainforest ... in the monsoon season ... at night. As you can imagine he spends a lot of time getting vehicles out of a tight spot!

This week, Geneva-based expats the Up 'n Atoms face up to the REME Rebels, an all-girl team of army-tank tinkerers in one of Scrapheap's most bizarre challenges to date. Our teams have just 10 hours to build a motorised bowling ball capable of toppling ten-foot skittles on a giant bowling alley.

A brave-hearted bunch of Scottish boffins take on a rabble of right-on rickshaw riders in an epic Scrapheap battle. Following in the footsteps of Barnes Wallis, their mission, should they choose to accept it, is to manufacture machines that can pitch bouncing bombs across water to breach the Scrapheap dams.

In the first of the new series, Scrapheap takes to the dusty dunes of a Guildford sand quarry as a team of hot-blooded Lancashire fire fighters take on some nerdy off-road enthusiasts in a battle to build sand-racers that can climb precipitous inclines and dig their way out of the deepest dusty trench.