Here is most of the guide:
A new Search and Rescue Center is being built on the Island of Sodor as a base of operations for Harold the Helicopter, Rocky the Crane and a new lifeboat named Captain. For the construction project, sturdy Jobi wood is imported from Hiro's homeland of Japan. Complications arise when Diesel takes the trainload of the lumber and has a close call over a seaside cliff! Thomas rescues him, but the Jobi wood is lost into the sea. For saving Diesel, Thomas is given the job of collecting new wood from the mainland, meaning an oceangoing voyage. When the barge carrying Thomas comes loose from its tugboat, Thomas is lost at sea, washing ashore on a strange place known as Misty Island.
Thomas discovers that the island has its own railway, and meets the three engines, known as the Logging Locos, who run it - a big, slow Class C Climax named Ferdinand, and two small twin engines known as Dash and Bash, who were sent to the island after causing trouble on the mainland. Thomas learns that lots of Jobi wood grows on Misty Island and tries to find a way to return to the Island of Sodor. Meanwhile, out at sea, Harold and Captain carry out a search party to look for Thomas.
FerdinandFerdinand is a gentle giant. He is a bigger and slower engine who is able to make special tweeting sounds with his whistles. He runs on wood and oil and can often be heard saying "that's right". Ferdinand is painted teal, with a gray lining, and is based on a Climax C type of logging locomotive.
Bash and Dash
Bash and Dash are mischievous twins who always finish each other's sentences. They were sent to Misty Island because they were naughty on the mainland, but now they always try to do their best for the Fat Controller. Bash & Dash are based on the Bear Harbor Lumber Company's Locomotive #1. This type of engine is known as a gypsy. However, their gearing appears to be on their backs instead of their fronts and their cabs appear much sturdier, as opposed to the open cab that their real-life counterpart possesses.
Scruff the ScruncherScruff is a boxy steam engine that works with Whiff at Whiff's Waste Dump. Like Whiff, he loves to be dirty and hates to be cleaned, making the dump the perfect place for him to work.
CaptainCaptain is a lifeboat that works with Harold at the new Search and Rescue Center on the Island of Sodor. Captain is very confident and is always in control when placed in emergency situations. He is painted yellow, blue and red with white striping.
Now I should point out that before Scruff's synopsis, there was this;
At the time this guide is being written, a photo of this new character is not yet available.
This probably explains why the trailer of the special hasn't been released yet, maybe due to the rendering of Scruff is still being worked on by Nitrogen Studios.