"Thomas & Friends", before the title was shortened, used to be known as "Thomas The Tank Engine and Friends". Since in many ways "Thomas & Friends" is quite a departure from the original series, this writeup will mainly be concerned with this current incarnation of the series (even though the episodes are considered to be seasons 7-10 of the overall series). See the Thomas the Tank Engine writeup for more information on the characters and the original books the series was based on.
When his son Christopher had the measles in 1942, Rev. Wilbert Vere Awdry began penning a series of children's books just for him called The Railway Series. He wrote the books about magical anthropomorphic railway engines on the fictional island of Sodor until 1972 when he ran out of ideas and retired. "Thomas the Tank Engine and Friends" was the television series based on the books which began in 1984 in Great Britain. Even though Thomas, the cheeky little blue tank engine, was originally a minor character, and not even introduced in the books until they were well under way, he became the nominal title character in the TV series, which was produced by Brit Allcroft (she had bought the television rights a few years earlier).
One unique characteristic of the series is that all the character voices are provided by the narrator (except in a retooled Japanese version). It seems to be up to their whims what each engine sounds like and they aren't always careful that the voices are entirely consistent episode to episode.
The first narrator of the series was none other than former Beatles member Ringo Starr. He was followed by Michael Angelis in 1986 (UK only). From 1991-1998 George Carlin narrated the U.S. series, which was ironic given the adult content of his stand-up routines. From 1998 to 2003 another major celebrity took over the narrating helm: Alec Baldwin. This was preceding Thomas' first feature length film - starring Baldwin - titled, "Thomas and the Magic Railroad" which was a gigantic flop and a total departure from the essence of the series. For instance, besides having talking railway engines and other vehicles, there's usually no magic on Sodor. It was too fantasy-based, wasn't in continuity with or in the spirit of the original series, and was just plain awful. This disaster is where Brit Allcroft got off that crazy train.
Thomas & Friends
In 2003, following the seventh season, the show got back into the original spirit of things, magic railroads disappeared, the title was shortened to "Thomas & Friends", and a new narrator and producer took over. The producer was Simon Spencer and the new narrator was Michael Brandon. The show was taken over by HIT Entertainment (who also does "Bob the Builder"), the theme song and format were reworked, episodes were extended from seven to eight minutes, and CGI bumper graphics were introduced. Also introduced was the first female character, Emily, a tender engine that was probably born from complaints that had been lodged against the show that it was sexist.
(According to all of my research it was the seventh season where this new look and format began and that it began in 2003 but I never see a copyright date for "Thomas & Friends" earlier than 2004. Yes I think I've seen every one, it's my toddler son's favorite show and we've TIVOed pretty much every episode. This could be because after the release of season 8 they went in and retooled some things, like the background music, in season 7 for re-release in the U.S.)
T&F airs in the U.S. on PBS and it runs 30-minute installments featuring three episodes each with brief CGI close-up graphics of one of the trains steaming by and little games and lessons in between them. The three episodes in each installment are all tied together in a theme, like shapes or colors or the different seasons. In many installments one episode can be about winter or Christmas and the very next one take place in the summertime. What season it is when the episodes air don't seem to matter.
The seventh and eighth seasons (which, like I said, both have copyright dates of 2004 in the U.S.) were very similar. The stories shifted from being very action-packed to focus more on morals and characters. They do indeed do a lot to develop the characters' personalities but there's plenty of action. Accidents happen in almost every episode, even though the information out there says that there are actually less accidents in these seasons due to complaints from parent groups. I've seen many episodes on VHS narrated by Starr, Carlin, and Baldwin and they don't have any more or less accidents, but oh well.
Most of the accidents that happen to the steam and diesel engines on the island of Sodor have something to do with the "troublesome trucks," the bane of their existence. The engines on Sodor have to shunt and haul freight on these mischievous cars who take great delight in causing trouble by refusing to move or try to go too fast. One skill each steam engine must learn is how to "biff" and "bash" them into submission. The troublesome trucks don't have names and rarely have involved conversations with the engines and are often destroyed or badly damaged in the crashes they cause. You might say that these are the only characters that are ever "killed" in the series, but their destruction doesn't ever seem to matter because Michael Brandon follows every accident with "Luckily, no one was hurt."
Another phrase often repeated in T&F is "You have caused confusion and delay!" and almost every time it is uttered by Sir Topham Hatt (he wears a top hat). He is the man that runs the railways on Sodor that was simply referred to as "the fat controller" in the early days of the series. He is never called this in the current seasons. Sir Topham Hatt accuses the engines often of causing "confusion and delay" after their antics, even though sometimes the troublesome trucks are mostly the cause of the messes. Apparently this is a lesson in responsibility as the engines are expected to deal with the trucks' incompetence (hmm... this sounds familiar). But the accidents do often happen because the engines are often childish and do stupid things out of spite, forgetfulness, or vanity. If I was Sir Topham Hatt, I would scrap all of them, starting with the trucks. Why can't he get trucks that aren't troublesome? Are all trucks that are created in this world this way naturally?
Frequently, conflicts arise between the steam engines (which all of the main characters are) and diesel engines. There is a long-standing rivalry between the two groups. Diesels derisively refer to the steam engines as "steamies" and tease them often. The main diesel character is simply named "Diesel" and he's the worst of all. This would be a perfect set up to teach the children a lesson in tolerance, like between these two train engine "races" but this elephant is always left sitting in the room. The children are never taught that there is anything wrong with all the steam engines disliking all the diesels just because some of them are mean and the diesels disliking all the steam engines just... well, because they're steam engines. There is even an episode where one of the steam engines is briefly ostrocised because of a rumors that he was friendly with the diesels and that all the steam engines were going to be scrapped. They learn the lesson that it is wrong to spread rumors but the steam engines are never lectured by Sir Topham Hatt that it was wrong to shun one of them just because they were seen talking to the diesels and at the end of the episode the two groups go on disliking each other. I found that troubling.
There is also a small rivalry between the tank engines - like Thomas - and tender engines - like Gordon - but it is not as pronounced or mentioned as often.
The joys the steam engines get out of their lives are the fun jobs they get, like taking children somewhere, hauling the presents train at Christmastime, taking the brass band to parties, and the like. Except for one episode in Season 9 (2005) where Thomas gets a day off none of them ever seem to get days off or even breaks, except at night where they go to Tidmouth Sheds and sleep. Sometimes they don't even get to do that. I found this also troubling. Their entire existence is just to work and without any compensation. Their only payment is gratitude, like when Sir Topham Hatt will declare they are "a really useful engine!" or they get to do jobs that are fun. Doing your job and doing it well is a good lesson. But something bothers me about how the engines are regarded and treated. They are not just train engines in this world, they are talking engines with human personalities and feelings.
The personalities of these engines are diverse and represent a broad spectrum of different human characteristics from cheekiness to vanity, from kindness to spite. T&F chose seven steam engines from the previous books and television episodes and one new one - Emily - to be the official main cast with Thomas at the helm. The rest are all secondary even though they sometimes have entire stories centered on them. The descriptors in quotes are from the roll call song that is played at the end of every episode of seasons 7, 8, 9, and presumably the forthcoming tenth.
"Thomas! He's the cheeky one..."
He is a small, blue tank engine, meaning he carries his coal in a tank, as opposed to a tender (a car full of coal always in tow). He is kind, caring, but can be quite naughty and childish.
"James! He's vain but lots of fun..."
James is the only one of the "elite eight" that is red and nobody is more aware of that fact than James himself. Vanity is the main aspect of his personality, a trait that often gets him into trouble. He is generally good but his snobbery can anger the other engines. He is a tender engine.
"Percy pulls the mail on time..."
One of his main jobs is indeed to pull the mail, his favorite job. He is a small, green tank engine and one of the youngest and shows his immaturity often by mispronouncing words. He is often used as a plot device to explain concepts and words to the kids as he often encounters things he doesn't understand and has to be corrected and/or lectured as to what they are by another engine.
"Gordon thunders down the line..."
Gordon is a big, proud, blue tender engine. He has great strength and speed and his main job is to pull the express passenger train. He is stuffy and a little curmudgeonly and looks down on the other engines often. But he still "gets too big for his buffers" and makes blunders that humble him somewhat. One of the big hills on Sodor is named after him, "Gordon's Hill" and its steepness is often used as a plot device to get engines into trouble (engines often get stuck on it, either running out of steam or carrying something too heavy).
"Emily really knows her stuff..."
She is Topham Hatt's first female engine. She is dark green and has a tender like Gordan and James, but has big wheels, which she likes to boast about sometimes. She likes to act as a big sister to Thomas and Percy and tell them what to do. She thinks she knows everything, an aspect of her personality that often gets herself and other engines into trouble.
"Henry toots and huffs and puffs..."
Henry is a big, green (same color as Percy) tender engine much like Gordon. But unlike Gordon, he sucks at carrying passengers (riding on Henry's train is quite a bumpy ride!). He prefers to carry things like logs and his favorite forest on Sodor is sometimes informally referred to as "Henry's forest." He often has boiler troubles and has been ill with them in more than one episode.
"Edward likes to help and share..."
Even though the "age" listed for him is 25 (honestly I don't know where Wiki is getting those ages) he is actually the oldest engine, older than Gordon and Henry. He is the kindest engine, albeit the slowest. He is, however, a big and blue tender engine but it must be his age that slows him down. As he is the wisest he rarely gets into trouble and when he does it's not likely to be his own doing. Talk of him retiring was a plot device in one episode.
"Toby! Well let's say... he's... square!"
He is an old tramway engine, a rare steam tram engine (as most of them are electric). He is one of the oldest and has the most experience, on par with Edward for never making any childish blunders as the other engines are wont to do. Unlike Emily who just thinks she knows best, Toby often actually does. He used to work on a special line in England delivering goods from farms but when that line was closed Sir Topham Hatt put him to use on Sodor hauling and shunting freight. He is the only brown engine on Sodor.
He is a green GWR pannier tank engine. His real name is Montague but everybody calls him Duck because he waddles like one. He made a very brief appearance in a season 7 episode but besides that he's been absent in the Thomas & Friends seasons. In the early days of the show he was on it often. Like most of the engines he's a hard worker who mostly hauled and shunted freight.
Donald and Douglas
They are identical twin tender engines from Scotland that have also not made many appearances lately.
Annie and Clarabel
These old fashioned light brown coaches are Thomas' favorite and the three are usually quite inseparable. When Emily first arrived on the island they mistakenly gave her Annie and Clarabel which caused Thomas to be very cross.
Bertie the Bus
He is one of the anthropomorphic vehicles on the island that is not a train engine. He is a red bus that loves nothing more than to show his speeds on the roads of Sodor. He has raced Thomas twice, once in the old Thomas the Tank Engine and Friends days and once in the recent seasons.
Elizabeth the Vintage Truck
She is, as her title accurately suggests, an old vintage truck. Like Bertie she takes passengers and goods on the roads where the engines cannot go. She has a little bit of an attitude and is really bothered by rudeness.
He is a very congenial black steam engine who is very sensitive, has a kind heart, and a big silly grin.
Diesel is a Class 08 diesel shunter, the first diesel engine on Sodor. He is a scheming trickster that loves making trouble and fun of the "steamies."
Even though she looks like a steam engine, she is a diesel engine. She is mostly black with a yellow hazard pattern on her front and rear. She is not quite as scheming or mean as the other diesels.
'Arry and Bert
These two identical twin diesel engines work at the smelter's and scrap yard on Sodor. Like Diesel they like to engage in spiteful tricks and make life general difficult for the "steamies."
An old diesel engine that would rather tell stories than set off pranks. He has an English West County accent (for Amerians, he kind of sounds like a pirate) and uses a lot of nautical slang. Fittingly, he works at Brendham docks. He has a yellow hazard patterning on his front and rear and is dull red in between.
He is a chubby, red, congenial crane engine who is in charge of the breakdown train and comes to help straighten things out and get the other engines back on their tracks after accidents.
He is a green railway traction engine who mostly works at the cement works. He loves to say "Do it right!" and that is indeed his usual work ethic.
He is a big maroon tank engine and when he first arrived on Sodor he had a spotless record. Predictably, that didn't last long, as naughty antics by Thomas and Percy got him a spot on that record not long after he'd arrived.
With ten driving wheels, this orange-yellow engine is the longest and strongest on Sodor. He loves peace and quiet and doesn't often get it.
She is a large yellow tender engine and is sensitive to what the others think of her. When she first arrived she was embarrassed to be taking empty freight cars.
He is a lazy silver diesel engine who likes to run away from his work. He is short and stout and speak with an American southern accent.
Cranky the Crank
He is a crane that loads and unloads stuff at the dock. He's always cranky because he never gets to go anywhere and often has to endure Salty stories.
Narrow Gauge Engines
These engines are smaller than the rest who work the narrow gauge lines. They mostly report to the narrow gauge controller, Mr. Percival, as the other engines report to Sir Topham Hatt.
Rheneas and Skarloey
These two are often featured together as the are best friends. Both are red. Skarloey is the oldest narrow gauge engine. Rheneas is also very old.
He's a well-mannered little green engine. He has a strange-looking funnel after his original one was busted off in an accident.
He's a little narrow gauge diesel engine. He is orange and black. The interesting thing about Rusty is his gender sometimes came into question. He was originally referred to in Season 9 of the American version as female whereas everywhere else, including the books, he was referred to as male. The bits where he was referred to as female have now been renarrated.
He's a the tallest of the narrow gauges and painted bright orange. He speaks in a Scottish accent and loves to complain about things.
It's one dark blue engine, but with a different head and personality at each end (one is Mighty and one is Mac and they have trouble getting along sometimes). It is an actual engine type (a Doubled-ended Fairlie) and was introduced in the Season 9 "Might Mac" episode but hasn't been seen much since.
He's a little orange engine that works on a distant branch line, the Bluebell Railway. He makes occasional visits.
He is big, silver, and fast, even faster than Gordon. He is only on the island when the Duke and Duchess of Boxford arrive for a visit as he is their personal steam engine. He is very egotistical but was humbled once by losing a race to the old and slow Edward ala "Tortoise and the Hare."
They are too numerous to mention them all and most are quite unimportant. I'm only going to list a few off the top of my head.
Sir Topham Hatt
Or "The Fat Controller." Pretty much runs the railways on Sodor. Sometimes it seems like he runs everything as he also orders around the non-engine vehicles. He's fat, wears a black suit, and of coure a black top hat (without the hat he's bald). He booms "You have caused confusion and delay!" when an engine messes up and "You are a really useful engine!" when they do good. He is always flanked by two or three other guys whose roles are ambiguous. Maybe they're his body guards.
Sir Topham Hatt's wife.
The narrow gauge controller. He tells the little narrow gauge engines what to do, but reports to Sir Topham Hatt. He wears a black suit, black bowler hat, and glasses. He is also usually flanked by two other mysterious no-name guys.
He's the farmer on Sodor who often uses the engines to transport eggs, chickens, and the like.
There is a toy version of just about every character. For every engine there is a bigger, wooden figurine, and a smaller metal (and more durable) figurine sometimes called "take alongs." The wooden figurines are beneficial to have because they fit the wooden tracks that you can purchase. If you buy enough of them and things like the sheds, washdown, etc. you can almost recreate the island of Sodor yourself. But if you're not interested in that here's a hint for parents out there: the "official" Thomas & Friends Island of Sodor tracks are compatible with and identical to the Imaginarium tracks - which are much less expensive.
Thomas & Friends is filmed at Shepperton Studios which is located in Shepperton, Middlesex, England. The studio is about the size of an airport hanger. This show is not exactly a cartoon; they are all real toy engines steered by remote control on scale model landscapes and tracks. The whole point of the looks seems to be what would happen if a toy railroad set up (trains, people figurines, fake trees, hills, etc) came to life. The set would be quite impressive to see in person, I'm sure.
The faces of the engines are not animated. There is a set of sculpted facial expressions (happy, sad, surprised, cross, neutral) for each one and they change after cutaways, not right before your eyes. The same goes for people like Sir Topham Hatt, kind of (his facial expressions seem to be rendered by differently-painted heads).
The Theme, Intro, Etc.
Every episode in the current incarnation of the show begins with an opening sequence with Thomas puffing around the island while the lyricless theme music plays. The theme music is mostly piano ragtime music like Scott Joplin would have played and seems to represent the early 20th century era the show is apparently set in. Then there's a narrated introduction to the island of Sodor that begins as CGI and morphs into real filmed footage. The 2005 (ninth) season intro is longer - before the main title theme starts up there is another CGI intro featuring the Thomas the Tank Engine book being opened and a reading of the first page which is a dedication supposedly by Awdry to his son Christopher. It begins with "Dear Christopher..." and ends with "...Your Loving Daddy." Awww, how touching.
Every show ends with a role call song (mentioned above) with the same theme music only with lyrics. Then there is a close up of a smiling Thomas, his eyes going up and down as he watches the closing credits roll.
The 10th season began on PBS Kids during Labor Day Weekend 2006 and featured 14 new episodes and four new characters: a plane named Jeremy, a new tank engine named Rosie, a new crane named Rocky, and a warhorse engine named Fearless Freddie.
IMPORTANT UPDATE 6/13/2007: Millions of Thomas toys have been recalled because the toymaker, in their infinite wisdom, decided to use lead paint. Read about it here. And here is the official recall site.