Flatbeds of Fear

S18, E3: A delivery of pipes is being unloaded at Brendam Docks. But the engines start to hear scary spooky noises and soon Salty has them all convinced that it's the sound of the Flatbeds of Fear. Only Emily insists that there must be a sensible explanation, until she hears the sound herself and gets frightened. But it turns out Emily was right about their being a sensible explanation. The sound was just air blowing over the pipes!