Agnes, Ruth, Lucy and Jemima are coaches on the Skarloey Railway, whilst Beatrice is a guard's van.
The coaches have been part of the Skarloey Railway ever since the beginning of its history. When Skarloey was to take them out for the first time to take the directors' train, Agnes was very suspicious and warned the other coaches to "be on their guard". She warned Skarloey that they would keep a sharp eye on him, but after Skarloey began to bounce when Mr. Mack shut his regulator too quickly, they thought he bumped them on purpose and bumped him back, causing Mr. Mack to fall into a set of bushes. He was so cross that he rode in Beatrice for the rest of the journey. However, when Skarloey was given a pair of trailing wheels and a cab, the coaches, even Agnes, could not help but feel impressed by it.
When the railway was facing hard times, the coaches were so full, that passengers had to travel in Beatrice on occasions.
In 1955, when Sir Handel and Peter Sam came to the Skarloey Railway, they immediately began to dislike Sir Handel for calling them "cattle trucks", so they decided to seek revenge by holding him back on the hill. When Peter Sam had to take the coaches out, they preferred him over Sir Handel, given his good nature, despite a small incident where they told him that he left the Refreshment Lady behind after Henry jokingly threatened to leave their passengers behind. They still held a grudge against Sir Handel when he had to take them out for Market Day and when Sir Handel had to stop for sheep that strayed onto the line, the coaches thought he bumped them on purpose and derailed him by bumping him onto a set of points. Skarloey was the only engine left and he scolded the coaches severely for their bad behaviour and warned them not to play tricks on him. They were left feeling ashamed of themselves. Since then, especially after Skarloey went away to be mended, they never play tricks on Sir Handel that involve derailing him and they all got along with him. Despite this, they can still be awkward on occasions and act in a way that only Skarloey and Rheneas know how to handle.
One summer, the railway had so many visitors that there were not enough coaches to supply the passengers, not even Agnes, Ruth, Lucy, Jemima and Beatrice could carry them all. Beatrice was built with a buzzer and when more tourists travelled in her, Sir Handel was so impatient that he accidentally left his guard behind. Luckily, one of the passengers was able to push Beatrice's buzzer to alert Sir Handel's crew.
The coaches like all the engines, Sir Handel least of all for referring to them as "cattle trucks". They were also mistrustful of Skarloey at first for being bouncy. On the contrary, they took to Peter Sam right away, and he even called them his 'dears' whenever he took them out.
Agnes is a deep-voiced first-class carriage who looks down on the others, who are second (Ruth) and third-class (Lucy and Jemima). Agnes appears to be the leader of the five. All four coaches look down on Beatrice and claim that she "smells of fish and cheese". Beatrice is, however, very useful. She has a ticket booth and an emergency buzzer and sometimes even carries passengers when the coaches are full.
Jemima is somewhat deaf, when she first met Peter Sam saying "Come along, girls! That's the way, my dears, gently does it!"
The coaches are genuinely nice and quiet like many other coaches, but can be rude and pushy if an engine does not treat them properly. They can occasionally be silly and awkward and play tricks on the engines by pushing them down a hill without thinking about what they are doing, something that Sir Handel and Duncan struggle with. However, Skarloey and Rheneas, given their many years of experience, always know when to be stern with them when they misbehave and put them in their place.
Ruth, Lucy, Jemima and Agnes are based on the Talyllyn Railway's first, second, third and fourth carriages respectively. Agnes differs from the others as she, like Talyllyn carriage No.4, was built by Lancaster Wagon Co. and has straight sides rather than curved. Beatrice is based on the Talyllyn Railway's first guard's van.
Agnes, Ruth, Lucy and Jemima are painted blue with cream window surrounds. The words "SKARLOEY RAILWAY" are painted under their windows in dark blue (only appears in Four Little Engines), and the numbers "1" (Agnes), "2" (Ruth) and "3" (Lucy and Jemima) are painted on their doors in gold, indicating each coach's class. Beatrice is painted entirely blue.
- In the fourth illustration of "Old Faithful", Skarloey is shown pulling five coaches instead of the usual four.
- Their models built by the Rev W. Awdry are now on display at a Narrow Gauge Museum in Tywyn, Wales, UK.
- The coaches were featured on the 1986 single cover of Oh L'amour, a song by English synthpop duo Erasure. They were incorrectly painted dark green with cream windows and Beatrice was portrayed as a coach rather than a guard's van.
- While planning the history of the Skarloey Railway, Sir Handel Brown was said to have five daughters. Their names would be used for the Skarloey Railway Coaches, with the exception of Jemima who took the place of Hilda.