One day, as Thomas pulls into Maithwaite, he rolls over some uneven sleepers. As he does so, his wheels make a clanging and clacking noise. He rolls back and forth a few times until the Fat Controller stops him. He tells Thomas that he needs to collect the brass band who are coming to perform a special concert on the station platform.
Thomas puffs off to pick up his passengers. When he sees the Brass Band waiting, he is very happy. Today, they have an extra band member. The conductor explains that they have an extra-special soloist for their extra-special concert. Thomas sees the soloist is carrying a large case. The conductor tells Thomas that the case contains a xylophone. Thomas cannot wait to hear the xylophone in action at the concert.
The band members climb aboard and Thomas heads off towards Maithwaite. On the way, the band members practice and Thomas joins in by blowing his whistle. Thomas feels very proud as the children cheer as he passes by. Thomas is enjoying himself so much that he almost misses a red signal. Thomas screeches to a halt just in time to let Gordon pass on the main line. Thomas had stopped so suddenly, that the band had all toppled over when he had braked. Thomas apologises, but the guard says no one had been hurt, so everything is fine. Unfortunately, this is not true; the soloist's xylophone is in pieces. Thomas feels very sad, as does the soloist.
As Thomas rolls sadly into Maithwaite Station, he passes over the uneven sleepers again. The conductor thinks the sound is great and tells Thomas to do it again. This gives the conductor a great idea.
Later, during the extra-special concert, when it is time for the solo, the soloist climbs aboard Thomas. As the conductor directs them, Thomas and the soloist run over the uneven sleepers. Thomas enjoys making music, but he still wants to hear an extra-special xylophone solo some day.