Kim Jong-Il refused to fly, IIRC. Didn't go anywhere his trains (he had a few) couldn't. Kim Il-Sung also travelled by train, but I'm not sure if he refused to fly. He toured Eastern Europe by train once. Kim Jong-Un's been to Hanoi by train. Supposedly, the Kims travel with three trains. Leading one to ensure the track's safe, middle one luxury (& armoured) accommodation for the divine Kim, & 3rd one for supplies, guards & servants.