'Arry and Bert/Behind the Scenes

Television Series
'Arry and Bert are fictional standard gauge twin diesel locomotives created by Britt Allcroft and David Mitton. They work on the North Western Railway. Despite being twins the two are not quite identical: Bert has more stubble.

In 1998, 'Arry and Bert made their debut in the fifth series of Thomas the Tank Engine and Friends in the episode, Stepney Gets Lost.

After being absent in 2006, 'Arry and Bert returned to the series in 2007.

When the show transitioned into full CGI in 2009, 'Arry and Bert were absent for a year and later returned in the fourteenth series.

From their return in 2010 until 2011, Kerry Shale provided the voices for 'Arry and Bert in both the British English and American English dubs of the series. In 2012, William Hope took over the role of Bert, leaving the role of 'Arry to Kerry Shale.

'Arry and Bert are based on the BR Class 08.

Gauge 1 Models
'Arry and Bert's models were designed to run on Gauge 1 track. They were built out of moulds of Diesel's model. Their buffers and couplings were made by Tenmille.

'Arry and Bert's chassis' were constructed from scratch (CNC), utilising Tenmille split-spoke wagon axles. They were powered by electricity from the track via the pickups on the metal wheels.

The eye mechanism had two servos, one for up and down movement and one for left and right movement. The up/down servo was attached to the body. The left/right servo had a rod attached to the arm, which connected to a bracket. The eye balls were coupled to the bracket and locked in by the face-plate, so whenever the servos were powered, the eye balls would move however the crew member desired.

'Arry and Bert have had modifications throughout the model era. These include:
 * Series 6:
 * The position of their hazard stripes changes, giving the illusion of their faces becoming smaller.
 * Their side rods change from silver to black (likely a remnant from Splatter and Dodge).
 * The tops of their running boards change from yellow to black.
 * The "Sodor Ironworks" writing on their sides became taller.
 * Their models were significantly less weathered than the previous series.
 * They gain handrails on their cabs.
 * Calling All Engines!
 * Their horn sounds changed to Diesel's at three and five steps lower-pitched.
 * Series 12:
 * Their CGI faces became smaller (as a result of the animators tracking the scale of the eye plate rather than sizing to the scale of the face).

Present Day
After production of the model series wrapped in 2008, most of the models and sets would be put into storage, with some being put on display at Drayton Manor Theme Park. All other models would be logged and referenced in 2009 by HiT Entertainment, from this HiT would decide on which models were to enter storage once again, which would be given to crew members and which to be disposed off. Due to only having one set of models made in gauge 1 scale, 'Arry and Bert's models would stay under HiT and later Mattel's ownership.

'Arry and Bert's models used to be on display in Canada at Nitrogen Studios with their sly and cross faces. After Nitrogen left the series, the models were returned to storage.

Fonts
The following fonts were used on 'Arry and Bert's Gauge 1 models:
 * Arial

Close-up model
Close-up shots of 'Arry and Bert's cabs were required for scenes in where they had to interact with close-up scale figures. Only one model was ever built which was not complete and only portions of the cab were built. 'Arry and Bert's close-up model only appeared in the Calling All Engines! Learning Segments, Which Things are the Same?.

CGI Models
In 2009, the series introduced Computer-Generated Imagery (CGI) as a replacement for the show's long-standing live-action models. 'Arry and Bert were recreated from scratch in CGI by Nitrogen Studios. However, test footage was created by Stardust Pictures as they recreated scenes from Thomas and the Stinky Cheese. Their models were "hand-sculpted" in Maya, a 3D animation and modeling software. Photographs of 'Arry and Bert's Gauge 1 models were used for reference. According to Greg Tiernan, every detail of the original television series models for each character is carefully reproduced in the CGI model. The models are subjected to many rounds of review before they are submitted to HiT Entertainment for final input and approval.

'Arry and Bert have had modifications throughout the CGI series. These include:
 * Series 14:
 * Their faces became slightly larger in size.
 * They gained new horn sounds.
 * Series 18:
 * They each gained a tail-lamp.

Fonts
The following fonts were used on 'Arry and Bert's CGI models:
 * Arial