Each year for nearly a decade, a dedicated group of railway enthusiasts has been making its way to Japan to explore the small local railways, which branch out like so many veins and arteries around the country.

The fascination is not only with the railway companies and the trains themselves -- many of striking varieties -- but with why some of these local networks were constructed in the first place, in backwaters that open to the countryside.

The minor lines, which seem to continuously spring up, offer those who come on the trips -- usually held once a year -- a challenge and an opportunity to explore and learn about a particular area of a network. They also offer a peek into rural Japan.

"In the past few years, we've covered a fair chunk of the Japanese railway network, and maybe not all of the minor railways, but we've probably visited most of them," Peter Dibben, a member of the Japanese Railway Society (JRS), said in a recent interview.

"I know I haven't done all of them because they keep creating new ones," he added.

The JRS was founded in Britain in 1991, and aims to promote knowledge of Japanese railways in the United Kingdom and abroad, bringing together people from around the world who have a common interest in Japanese railways.

The society publishes a quarterly journal called the Bullet-In, which is the only regular publication about Japanese railways that is not in Japanese.

Dibben, a retired chemical engineer, is one of the organizers of the informal trips by a small group of JRS members to Japan, to minor railways that are run privately or in a private-local authority partnership as third-sector railways, mainly in rural areas.

The group of between five and seven JRS members travel together with a Japan Rail Pass for around two weeks and focus on one area of the network to explore, while making time to experience the local food and culture along the way.

"It took us something like 10 days to do every single line in Hokkaido," Dibben said. "You're up against only a handful of trains a day on some lines, so you have to work around the timetable."

To date, they have ridden on around one hundred minor railways.

In the early years, the JRS organized trips with tour companies to visit Japan, but certain train lines were not made for big crowds. Smaller railways pose a logistical nightmare.

"There are a lot of very small railways in Japan, and taking 30 odd people on a single coach train is probably not a good idea," Dibben pointed out.

While the JRS continues to arrange bigger tours to Japan every few years, with a group of enthusiasts dedicated to smaller, local lines, they started informally organizing holidays together.

Their first trip was in 2008, with the first focused trip of an area to the Tohoku region coming in 2009.

They have since been to the northernmost station in Japan in Wakkanai, Hokkaido, down to Kyushu in southwestern Japan, with journeys to places like the last stop on a local line that is served by just three single carriage services a day. On the day they were traveling, one of the morning trains had been canceled.

The group makes an effort to ride the railways in daylight to appreciate the type of area the line was built to serve.

Originally, Dibben gained an interest in Japanese railways when he first visited Japan for work because his company had a contract with Hitachi.

"Occasionally we got the odd bit of time off, and I just used to wander off down to the station and see what was happening," he explained. "Being a rail fan anyway what else would you do? So that's how I got interested in Japanese railways."

One of the draws of Japanese trains is also the "sheer variety."

"You've not only got the different companies, it's not like they all run the same kind of train. The photographs you take on one railway look different from another railway. If the trains are the same, they're probably a different color."

He is also fascinated by why these minor railways were built. While railways in rural areas were generally intended to open up the countryside, some could be based on pure speculation.

"When you've ridden some of them you wonder why they were built in the first place, never mind how they managed to survive," he said.

"It does give you a glimpse into rural Japan in some ways."

Many other members of the JRS -- with around 200 members in over 10 countries, from the United States, to Germany, to Australia -- have worked or lived in Japan, or gained an interest in its activities through Japanese model railways.

Along with the bigger tours to Japan, the JRS hold informal meetings throughout the year across Europe and Japan.

Until recently Japanese-made model railways were of much higher quality than British ones, according to Dibben, and so some people got into Japanese railways through building models.

Dibben himself has built a model of a fictional minor railway in Japan, which he has exhibited two or three times a year at model railway exhibitions in England.

The common interest of Japanese railways has also led to international friendships developing over the years. The JRS has Japanese and non-Japanese members who live in Japan as well, who arrange and go on weekend rail tours around the country.

Just as Dibben's group visits Japan for Japanese railways, some Japanese members visit Britain to explore British railways too, and they try to link up when they are visiting each other's country. The payoff is when they run across a fellow railway enthusiast.

"Occasionally, when we were out there we came across somebody obviously standing at the end of a station platform with a camera. Not many of them speak fluent English, but sometimes you can actually have quite a good chat, because it's a common interest. It's happened. In England it happens all the time," he said.