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This article is about the engine. You may be looking for the Story Library book.

Rosie is a lively little tank engine who idolises Thomas. She works as both a shunting engine and a mixed traffic engine.


Thomas & Friends

Rosie began idolising Thomas to the point of hero-worship and imitation. Though this is said to be the most sincere form of flattery, it only served to irritate Thomas whilst he was trying to deliver a special birthday post train to Alice at High Farm. He even started to try and avoid her, but after Thomas had an accident in the course of delivering this train, Rosie helped him and he started to respect her.

Rosie was later called to help Thomas shunt trucks until Hector frightened her away.

Rosie was charged with acting as a back-engine to Emily with the funfair special. Wanting to take the train herself and thinking she was doing Emily a favour, Rosie succeeded only in creating confusion and delay on a grand scale, but eventually set things right.

Rosie rescued Thomas when his fire went out after playing a game of "Splish, Splash, Splosh". She later let Diesel take her train of flowers which was headed for market.

One day Rosie had a cracked wheel, so Thomas and Butch brought her a new one.

On Sodor Surprise Day, Thomas bumped some coal trucks to surprise Gordon, but ended up surprising her instead. She is later seen being cleaned up with Whiff at the washdown and joins Gordon and Thomas at Callan Castle to see Harold decked out in bright lights to make Gordon laugh.

Sometime after she was repainted into her red livery, James challenged her to a race. When Rosie realized that there was something wrong with James' brakes, she warned him to go to the Steamworks to have them checked before they got worse. James did not follow her advice, and as a result, when he sped down Gordon's Hill, his brakes would not work, and he went on a runaway until he crashed into the wall at the end of Tidmouth Sheds.

Soon after, James went to the Vicarstown Goods Yard, looking for Henry's train to take to the Mainland. Rosie told him that she knew they were important and that was why Thomas came to take them early.


Rosie is a friendly, respectful and helpful tank engine who likes Thomas very much. She and Thomas like to have fun, and also like to help each other when they are working. Rosie can be described as a feisty, energetic and free-spirited tomboy who is not afraid to do hard work. She loves to race just as much as she loves to be Really Useful.

Rosie also seems very eager to prove her worth, as evidenced by her wanting to help Thomas deliver Alice's birthday presents, or even attempting to pull a special train on her own. As of Season 21, she appears to have become more levelheaded and mature, serving as a voice of reason to James' arrogance.

Technical Details


Rosie is based on an SR USA Class 0-6-0T. Originally classified as the USATC S100 Class and designed for shunting duties in Europe during the Second World War, after the war ended, fifteen of these engines were sold to the Southern Railway where they were used as dockyard shunters at Southampton. There, they worked alongside the LB&SCR E2s (Thomas’ class). Both classes were replaced by BR Class 07 diesels (Salty's class) in 1962, though members of the class remained in service on departmental duties until 1966.

Four members of this class are preserved in the UK, including one at the Bluebell Railway, and several more exist in various conditions throughout the world.  In addition, several Yugoslavian-built copies of the S100 design also exist, including two that have been imported into the UK and modified to represent USA Class members.


From her debut up until The Great Race, Rosie was painted lavender with light grey tank panels, red lining and gold boiler bands. Her wheels were red with light grey wheel rims.

Starting from the twenty-first season onwards, Rosie is painted cherry red with dark raspberry tank panels, gold boiler bands and light grey lining. She has gold lining above her wheels and around her ladder. Rosie has the letters "NWR" written on her tank panels in light grey and the number "37" in light grey under her cab windows. She still retains her original red wheels with light grey wheel rims however.


Thomas & Friends


Music Videos

Learning Segments

Voice Actors


  • Rosie is the first engine of several things:
    • The first engine of an American class introduced in the television series and the second such engine (after Stanley) introduced in the franchise overall.
    • The first engine in the television series to have their debut livery changed permanently and the second character in the television series overall, the first being S.C. Ruffey.
    • The first engine in the television series to receive a number who did not already have one.
    • The first engine in the television series to be lettered for the North Western Railway. She is the second in the franchise overall after Emma.
  • Rosie's model is currently on display at Drayton Manor. Sometime in 2017, a part of her siderod had broken off.
  • In Red for Rosie, one illustration incorrectly depicts her with a tender.
  • Most merchandise lines depicted Rosie without the lip gloss and blush that she had worn prior to the twenty-first season. Her recently-released Bachmann model depicts her in her original livery when she first appeared in the TV Series and without her pernament headlamp.
  • A magazine fact file states that she works on Thomas' Branch Line, although she is yet to be seen doing so in the television series.
  • The My First Thomas & Friends' Railway Pals variant of Rosie was the first piece of merchandise to introduce her in her new red livery.
  • Since her debut, Rosie has appeared in every season and special except The Adventure Begins, which was set before she arrived on the railway, and the twentieth season, possibly due to her model being reworked for the twenty-first season and Journey Beyond Sodor.
  • Rosie has both her whistle and connecting rods in different positions compared to her prototype:
    • Rosie's whistle is positioned behind her rear dome whilst her prototype has its whistle positioned on the right side of the middle dome.
    • Rosie's connecting rods are attached to her middle driving wheels whereas her prototype has its connecting rods attached to the rear driving wheels.
    • Her funnel is also taller than her basis.
  • Rosie has had a few modifications throughout the television series, which include:
    • Season 12:
      • Her tail-lamp was removed.
    • Season 13:
      • Her face became slightly smaller.
      • Her funnel and steam pipes became thinner.
      • Her lamp-irons were removed.
      • A detail on her coal bunker had been pushed in.
    • Mid-Season 17 (starting with Percy's Lucky Day onwards):
      • She gained a permanent headlamp of the same design as Ferdinand's, mounted in front of her funnel.
    • Tale of the Brave:
      • She regained her tail-lamp.
    • Season 21:
      • She received a new cherry red livery with "NWR" painted on her side tanks and the number 37 painted under her cab windows; the lettering is a reference to the North Western Railway.
      • She lost her lip gloss and blush but she still retains her freckles.
      • She gained rivets across her cab, side tanks, smoke box, cylinders and the sides of her buffer beam.
  • Rosie is numbered 37 as of the twenty-first season; this number was likely chosen as she is the 37th standard gauge engine introduced in the television series.
  • According to SIF, Rosie was intended to have at least one other episode in the twenty-first season. This episode, along with seven others, were cancelled to make way for production of the twenty-second season. Due to this, it is unknown why she was repainted.


“Rosie was a cheerful, chirpy little tank engine. She was always pleased to meet Thomas. She liked him so much that she wanted to be just like him.”
The narrator introducing Rosie, Thomas and the Birthday Mail, tenth season



* RWS only | ** T&F only | --- Dropped
International Characters

* RWS only | ** T&F only | --- Moved location