Annie and Clarabel are Thomas' faithful coaches, whom he loves dearly and would never dream of being separated from them.
Annie and Clarabel both have seating accommodation for carrying passengers; Clarabel also has a brake compartment for luggage and a guard. The two coaches are nearly always seen coupled together, with Annie usually facing Thomas and Clarabel facing backwards.
The details of Annie and Clarabel's lives before 1946 are murky. In 1946, they were given to Thomas when he started working his own branch line. They have had several adventures, such as losing their guard and becoming runaways. Clarabel once derailed on a set of trap points when Thomas slipped on some oily rails, and had to be helped by Diesel.
Annie and Clarabel are respectful to all of the engines, but most of all Gordon and Thomas, and Daisy least of all for insulting them and Henrietta. They show a kind and caring side to everyone in the whole railway. However, despite their kindness and sweetness, when needed they can be stern, especially Annie, like when they scolded Thomas for teasing Gordon. Annie and Clarabel are best friends, but like all friends, sometimes they fall out.
The coach that was to be the basis for Annie was first built by a teenage Wilbert Awdry as part of a model railway layout. Many years later, after a long hiatus from modelling, a brake coach was built to match so that the Reverend's Thomas model would have a complete train. In the Railway Series, they are a pair of bogie coaches (i.e. each coach is supported on a pair of four-wheeled bogies or "trucks"). As currently illustrated, they appear similar to non-corridor suburban coaches operated by the LMS.
In the Railway Series, Annie and Clarabel were originally painted orange-brown and were later painted brown with a yellow stripe. In the television series, they are painted in an orange-brown livery with their names written in white on their sides. They were refurbished in the fifth season.
- Annie is the older of the two.
- The Hero of the Rails intro shows Annie and Clarabel with bogie wheels.
- Annie and Clarabel's models used to be on display at Nitrogen Studios but are now on display in Japan.
- Early illustrations of Annie show her shocked face, and this was carried on to later illustrations and most merchandise. This is likely intentional for easier identification.
- A real television series version of Clarabel (a former LNER "Sunshine" coach) has recently been put into service at the Llangollen Railway in North Wales.
- Originally, there were plans to give Annie and Clarabel 3D grey faces, similar to the engines in the twelfth season as it would be easier to animate.
- Annie and Clarabel have gone through several modifications. These include:
- Season 1
- Annie's front bufferbeam was lowered down to match the height of Thomas' buffers.
- Season 5:
- Their models become severally weathered.
- Their livery changed from a tan color to a orange-brown.
- They received new models in Sir Topham Hatt's Holiday.
- Their roofs changed from white to grey.
- Since the latter, their buffer housings changed from black to red.
- Thomas and the Magic Railroad:
- Their buffer housings changed back to black
- Season 6:
- Their buffer housings returned to red.
- Season 1