Chapter 1 - Bigger on the inside
Rainbow Dash lazed on a low hung cloud and read the latest Daring Do book.
It was better than ever before and she was just getting to the good part when she heard the strangest noise she’d ever heard. It was a metallic thrumming that defied imagination.
‘Weeeoooorp - weeeoooorp’
The next sound was hard to explain, but it was a bit like a muffled jangling sound, then
‘Veeeweeeeoooorp - veeeweeeoooorp - thud - creak’
A blue box appeared in sync with these sounds and out stepped a coughing grey pony wearing a red cylindrical item on his head.
“I wonder why I can’t stand. Maybe I'll just crawl - there we go! Here we are-oh, this isn’t London.”
Rainbow, wondering what in Equestria ‘London’ was - and furthermore how a blue box appears out of nowhere - flew down and landed in front of the grey pony.
The box had a small light on the top, lettering across the top of tall double doors that read ‘Police Public Call Box’, and a sign that read ‘Free for use of Ponies, Pull to open’ (which was funny as the doors had opened inwards) on one.
“Who are you and how did you teleport the box? My friend Twilight can’t teleport boxes that size, and she’s an ALICORN!” She said, hardly noticing the colt was wide eyed, with a mentally large and lopsided grin on his face.
“You’re talking! You’re not supposed to be talking, at least - not in english! And you’ve got WINGS!”
“Well, DUH! Have you been living under a rock your whole life or something?!”
“But - you’re a pony!”
“Yeah, so are you.”
“No I’m - OH MY GOODNESS! Will you take a look at that! Ha!”
The pony looked himself over for the first time. He was an earth pony with black mane and tail. The mane was parted perfectly over the muzzle, just over yellow eyes.
“Well thats interesting! I must have regenerated and by some amazing chance my biology must have locked onto that of this universe!”
“Come again?”
The colt sighed and opened the double doors with a hoof.
The inside was a red and orange chamber with a small stair leading up to a large raised platform which held a six sided table covered in various knobs, buttons, levers and what appeared to be a hoofwriter.
“Bu-wha-?”spluttered Rainbow, struck speechless.
“I know, it’s.”
“85% cooler on the inside. This is just impossible! How in the name of Celestia are you doing it.”
“It's Dimensionally Transcendental” said the pony matter o' factly, “And, um - not ‘bigger’?”
“Uh-huh.”
“Want to take her for a spin? I wouldn't usually let you immediately after meeting you - but since almost every time I meet someone new they end up traveling with me, what's the point in fighting it.”
“It travels?”
“She does. Want to?”
“I just met you! I don’t even know your name!”
“Me? I’m the Doctor!”
“Doctor who?”
“Well, it’s just the Doctor.”
Not really good, but not really bad either. I'll reserve judgment until I finish the other chapters.
You have several grammatical errors, such as:
Stick to one method of showing your onomatopoeia. Either * or ', not both. Also, you use onomatopoeia instead of describing. Using onomatopoeia isn't bad, but repetitive use isn't very good.
Extra period after the quotation mark. Remove.
Asterisk for no reason.
Unnecessary apostrophes.
For interruptions, use a "-" instead of apostrophes.
Some other odd things I noticed:
Not an error, but just say fez, it is way more simple.
First off, Twilight was able to teleport herself and three others in "Dragon Quest",while still a unicorn, so transporting a tall wooden box as an alicorn is definitely possible. Second, "colt" is a noun used to mean a young male horse, around the age of childhood. The correct noun for an adult male horse is "stallion".
The Tardis's psychic link to the Doctor automatically translates everything. While it is possible that the Doctor is surprised that a horse is talking period, HE WOULD NOT SCREAM. He would be excited, especially the 11th Doctor, who was giddy when he found fish vampires.
This is progressing too quickly. The Doctor doesn't just invite a random alien on board, unless it was an accident, some kind of danger, a companion, or a person that the companion knows.
And the term is not actually 'fish vampires'. They aren't either. They are an advanced extra terrestrial race that happens to be exactly like the earth born myth.