At night, when the other engines are asleep, you can still hear some other engines puffing down the line. This is the sound of the post train. City of Truro, Morgan and Markus all take parcels and letters all across the main line. They stop at every station between King's Cross, Euston, Pattington, and New Castle. They collect post from other trains, and drop some off to other engines as well.

One night, Markus was waiting for the mainline train. It was late. Soon, Evening Star came, and she was out of breath. "Sorry," she said, "The harbor had a jammed set of points. It took a while to fix it!" "I understand," said Markus, with some anger, "Just hope it doesn't become a nightly thing." Markus then headed off with his post.

The next morning, he was very tired and needed a good rest. "You okay Markus?" asked Trooper. "Yes, I was up all night, and I need a good rest." Soon, he backed down, and fell fast asleep.

The next night, City of Truro was heading down the main line, and he made sure to be on time. But of course, the Lorry that was to bring the post broke down, and City of Truro was delayed. He now had to wait long into the morning to get his delivery done.

Soon, the post men had been annoyed by the constant delays, and bought their own engine to take the post. City of Truro, Markus and Morgan were cross at this. "They blame US for their short comings!?!" asked Truro. "It's just so stupid!!" said Markus. "They can't admit when they are in the wrong!" said Morgan. Harry then came, and he asked what was wrong. The three engines then explained what had happened. "Don't worry about it," said Harry, "Soon, they'll get their up coming, and you can redeem yourselves."

The next day, City of Truro was returning after pulling a passenger train to Paddington, when he saw the engine that replaced him. He looked at the post men. "Why does this keep happening to us!?" asked one. An inspector came, and said, "It's because you refuse to look after your machines properly. Many of these engines are in need of a major overhaul!" City of Truro then said, "I'll take the post!" The men looked at him. "Aren't you one of the engines who made the post late?" "Because your lorries kept breaking down at the same point!! They need an overhaul!!"

Truro then took the post as fast as he could. When it was delivered, the head of the post office spoke with his staff. They then told him what the inspector said. The inspector then came and said, "If you can't take care of your machines properly, then you will be removed from your position."

Soon, the three steam engines were put back on the Post train, and this time they made sure to be on time, and they had different Lorries take the post. It showed a huge improvement, and the head finally buckled under pressure and spent money to fix the broken Lorries. City or Truro, Markus, and Morgan all still take the Post train, and they make sure, to always be on time, and have little delays.