const std::map<unsigned, TrackType *> &get_tracks() const { return tracks; }
LocoType &get_locomotive(unsigned) const;
const std::map<unsigned, LocoType *> &get_locomotives() const { return locos; }
const std::map<unsigned, TrackType *> &get_tracks() const { return tracks; }
LocoType &get_locomotive(unsigned) const;
const std::map<unsigned, LocoType *> &get_locomotives() const { return locos; }