It was when the respected General Secretary Kim Jong Un inspected a trial run of a newly-built tube train. While giving the accompanying officials precious instructions on the design of the passenger train, he touched a seat in a carriage. Referring to the need to put collapsible chairs in the train so that pushcarts or prams can be leaned against them, he said it would be good to put them in some carriages, not all of them. He added that not a few tube travellers might use pushcarts or baby carriages. That day he oversaw the trial run until late at night and emphasized that the tube trains should be made on the world level, out of his desire to provide the Korean people with more convenient and modern tube train. Thanks to his meticulous care, collapsible chairs came to be put in the newly-built tube trains with the signs of exclusive use put up, to offer convenience to travellers with pushcarts and prams.