The mad train smashed through the ice and snow as it blazed along the rail tracks. It had to, for if it didn't, it surely wouldn't be able to withstand the several frozen obstacles on its way. This train was not the cutesy and gentle kind that traveled from Ponyville to Canterlot. This was a state-of-the-art, heavy-duty train with special heating equipment and advanced hydraulics. Nothing that could reach the territory of science fiction though - after all, Equestria's technology was not so advanced that any of its contemporary technological feats could be considered fantastical, but nevertheless it's not like the ponies lived in the stone age.
The train went far - far into a mountainous, cold, and unforgiving region. Its purpose there was nothing else - other than to transport a group of creatures to the closest stop they could reach - in order to get closer to their destination.
There were seven passengers.
Passenger one and two - Twilight Sparkle and her trusty assistant - the dragon named Spike. She was the Princess of Friendship and the organizer of the expedition, and much of the planning was hers. Spike's role was threefold - deliver letters in case of emergency, to assist Twilight overall - and to be able to provide emergency heating if the lamps gave out.
Passengers three and four - Starlight Glimmer and Sunburst. A duo of highly skilled unicorns; the former being the queen of practice, the latter the king of theory. Although Starlight's rather eccentric marefriend wished to join, Twilight spent hours finding the least offensive way to explain to her that her qualifications were not quite in line with this task. After all, they had to be careful with their provisions and rations.
Passenger five - Moondancer. A fellow intellectual with a great amount of knowledge; perhaps in times exceeding Twilight Sparkle's in certain spheres. The light-yellow mare did her best to appear cool and controlled about the prospect of embarking on this expedition with her old friend, but her sheer excitement was clear as she behaved fairly hyperactively.
Passenger six - Seefar. A fairly unfamiliar figure, the Zebra acquainted himself with the rest of the group as a survival and mountainous-terrain navigation expert. He was hired by Twilight once she caught wind of his services, and offered him a generous sum to guide and protect them. He accepted without asking questions. Only during a brief conversation with the Princess, did he reveal that he embarked on this journey to find his sister, or her fate; for she was lost during an expedition of her own. He vented that as much as he wanted to do this for free, he still needed the money to fund his search should this one turn out to be a dud as well. Twilight understood.
This should've been it. The unicorns were skilled spellcasters, and they did not need to hire any real security. What food they needed was provided by Seefar himself, for he was also an expert in food preservation, and had prepared many rations in the form of MRE packages. The passengers also constituted scholars and fairly educated individuals - Spike learned a thing or two working so much with books, and this Zebra turned out to know a fair bit about geography and geology too.
Yet, there was one more. A passenger who was able to get on-board by showing desperation - showing distress at the prospect of not joining. A passenger who Twilight did not expect to even take the slightest interest in this.
Passenger seven - the Element of Kindness, Fluttershy.
Nopony knew why she was this hellbent on coming. The call to let her join was Twilight's. 'Officially', Fluttershy said she wanted to see the local butterfly species, for they were rare and quite unique to that area.
'Officially', Twilight gave her the greenlight for the sake of studying the local fauna.
Yet, Twilight was curious - why Fluttershy mentioned the presence of butterflies...knowing that they were going deep into a cold mountain range.