Members of the brigade's community safety team hope to enter the record books by finishing the race next Sunday (April 24) with the fastest time in a four-person costume.
Lee Small, Stevie Clifford-Tucker, Mick Palmer and firefighter Jim Lafferty were inspired by the example of the Wolverhampton Bobsled Team, who dress like the Jamaican bobsled team of Cool Runnings fame and hold the current mark of 6 hours 23 minutes and 3 seconds.
Marketing Manager Ruth Beck will guide the team as they try to negotiate the 26.2-mile course in the plastic fire engine, complete with windscreen, lights and its own sound system.
Watch manager Lee Small said: "It all came about after Stevie saw the bobsled team at last year's marathon and thought we could do the same with a fire engine.
Costume includes sound system 'to warn people we're coming'
"It has taken us 10 full days to build the light-weight plastic fire engine and we've made it look as realistic as possible with the correct branding and it even has lights and a sound system so we can warn people we're coming."
The brigade will be represented by 47 of its employees at this year's marathon, including firefighter David Badillo, who is stationed at North Kensington .
He is running for Jade, the daughter of fellow firefighter Rob 'Ollie' North. The mother-of-two has been diagnosed with Huntingdon's disease and the money raised will be used by the family to create special memories before the disease takes hold. You can make a donation to the cause on his fundraising page .
If you're planning to watch this year's marathon, you can check out our handy list of spectator information .