Philippa, better known as Pip, and Emma are two diesel-electric locomotives which make up a BR HST InterCity 125 train set.
When Gordon took a railtour to Carlisle, Pip and Emma were asked to take the Express back to Tidmouth for him. Pip's cooling system was faulty, but Emma was in order and so off they went. Unfortunately, Emma failed near Crovan's Gate and James had to pull them back home. The engines were quick to befriend Pip and Emma, and after Gordon had returned, Douglas took them back to Barrow-in-Furness.
In 2010, the Fat Controller purchased them to run a faster service to London following Privatisation. They brought Prince Charles to unveil a bust of the Thin Clergyman at Tidmouth in celebration of the Clergyman's one-hundredth birthday.
Philippa, who prefers to be called Pip, and Emma are kind and friendly. They quickly became good friends with the other engines. Although they suffered problems with their cooling systems, they are efficient and reliable.
Pip and Emma are based on the British Rail Class 43 HST. This engine holds the world record for fastest rail speed for a diesel: 238 km/h or 148 mph. The Mail Train is another member of this class.
Pip and Emma are painted in the original InterCity 125 livery of yellow and blue. After they were bought by the Fat Controller, the words "InterCity 125" and the BR logo which were painted on Emma's sides were replaced by "NWR". Emma also has a red and gold nameplate. At the start of Thomas and His Friends Pip is seen wearing her old BR guise, it is unclear as to whether or not she eventually had these replaced by the letters "NWR", or if she later received a nameplate.
- Gordon the High-Speed Engine (Pip does not speak)
- Thomas and the Fat Controller's Engines (Pip does not speak)
- Thomas and his Friends
- Pip and Emma happen to be the names of two siblings in the Agatha Christie novel "A Murder is Announced".
- The phrase "pip emma" was also used in the signals developed by the British Army signallers in the First World War to mean post meridiem, or p.m.
- "Thomas and his Friends" marked Pip's first and only speaking role. Until then, only Emma had spoken.