(CNN) — China's rail system is one enormous mass of statistics.
It's 120,000 kilometers long (second largest in the world after the United States) and has the highest passenger-per-kilometer ratio in the world -- 1,060 billion passengers in 2013, according to the National Railway Administration of China.
But for one Beijing-based "photoworm" -- as photographers are dubbed in China -- it's far more beautiful than a bunch of big numbers.
Wang Wei, 25, is possibly the most passionate rail fan in China.
Over the past decade he's braved frostbite, unreliable timetables and months away from home while traveling an estimated 300,000 kilometers to capture the country's rail network and its trains in pictures.
Since then, Wang has become a mini-celebrity.
He's been interviewed by more than 20 Chinese and overseas media outlets, and even been the subject of a Chinese television documentary.
What's more, he has two books being published in China later this year.
"Zhui Huo Che" (Running After Trains) is a photo book featuring his experiences and photography techniques.
Wang often waits hours in sub-freezing termperatures to get the right shot, like this one of a CRH38B high-speed train in Heilongjiang Province.
"My Jing-Zhang Railway" is an illustrated book showcasing Wang's photos and interviews with people who have worked and lived on the Beijing-Zhangjiangkou line, China's first Chinese-designed and built railway.
"Chinese official have seldom promoted the beauty of the railway and trains," says Wang. "They have never taken pictures of what I've been taken.
"Instead, they take photos of leaders delivering a speech, cutting ribbons.
"I feel the railway belongs to each of us, everyone has the responsibility to promote it if they love it."
CNN: It's been two years since we last talked. Where have you been lately?
Wang Wei: The 200-kilometer Southern Xinjiang Railway (Tianshan Mountain section) stopped running in February 2015, so I brought my dad and three friends there last December.
It was really cold in Southern Xinjiang in December -- around minus 30C (minus 22F).
Even worse, we were told there were wolves in the area and they're very active at night, which was during my shooting times.
We decided to dig a hole and burn branches inside. The fire helped us drive away the wolves and warm ourselves.
Most important, I got the photos I want.
I also visited Japan and Germany in the last two years.
CNN: What impressed you the most during the trips?
Wang: The railway culture of Japan and Germany moved me a lot.
In Germany, they can buy the abandoned rails and trains for cheap, about RMB100,000 ($16,110) for two compartments, which is around one-tenth of the price in China.
They (often) retain the original look of their rail cars and turn them into hostels and restaurants. Really lovely.
In Japan, when I took photos of the trains, the staff was friendly and gave me useful instructions like where to get the good angles and so on.
This is impossible in China. Here the staff will only tell you go away.
You can also see quite a number of books featuring railways in Japan.
We have very limited materials on railways in China.
The length of China's railway system is the second longest in the world, and the history of Chinese railways is more than 100 years old.
I really wish the culture of the Chinese railways can catch up.
CNN: How did you get into railway photography?
Wang: I am a Beijing native and grew up by a train station.
These 1960s steam locomotives in use in a coal mine were captured in 2009. Today, the locomotives are retired.
I started taking railway photos in 2005 when I was 15.
I have a deep connection with the trains and railways. From my window (in my home), I can see trains every day.
The first photos I took were of trains at Beijing North Railway Station, which is next to my place.
CNN: What's the secret of a good railroad photo?
Wang: I usually make a plan two or three days before shooting.
According to the train schedule, color and type, I will think about light and background -- should it be directly light or back lit, things like that.
It's actually not too complicated.
CNN: Which have been your favorites places?
Wang: The Greater Khingan Mountains.
The Qinghai-Tibet extension rail.
South of Xinjiang.
And the Yunnan-Vietnam Railway's China section.
CNN: Any new trends in the train industry you've noticed?
Wang: The new high-speed trains are a growing influence everywhere.
In my eyes, the new trains aren't as beautiful as old locomotives.
However, from a passenger's perspective, it's good to enhance the speed.
CNN: What equipment do you use?
Wang: A Nikon D800 and a 28-300 VR lens.
It usually happens all of a sudden -- the train comes and there's no extra time for me to change lenses so I need a multiple-use, long-haul lens like that.
CNN: How do you travel to your destinations?
Wang: I use every form of transportation depending on where I go.
Trains and cars half of the time, and on foot the other half.
During my trip to northeast China in October 2011, I walked more than 186 kilometers in 15 days, not including the mountains I climbed. It was the only way I could reach the places I wanted to go.
CNN: How long do your photo expeditions usually take?
The narrow-gauge Kunming-Hekou Railway was built by a French-led concern from 1904-1910.
Wang: Depends where I go -- the journey usually takes from 10 days to a month.
The longest journey I took was a 56-day trip covering seven provinces -- Beijing, Gansu, Xinjiang, Qinghai, Shannxi, Yunnan and Guizhou in the summer of 2011.
CNN: Any difficulties during any of your missions?
Wang: To me, the difficulties are finding angles and waiting for trains.
I love the high angle, so I usually climb mountains to take photos.
Some of the mountains are steep and have dangerous wildlife, like snakes. So I need to be very careful.
At night, it's even harder to climb.
The trains often change schedules according to the weather or other unpredictable reasons, so it's quite normal for me to wait in one spot a whole day without seeing a train.
CNN: Is your family supportive?
Wang: Like many Chinese parents, they thought I should go to college and get a degree.
So at first they didn't support me at all.
But when they heard the experiences of my journeys and saw my photos were getting better and better, they were OK with it.
My dad sometimes will join me on photo shoots.
Story originally published June 2015.