sigc::signal<void, Vehicle &> signal_vehicle_added;
sigc::signal<void, Vehicle &> signal_vehicle_removed;
sigc::signal<void, Block &, Train *> signal_block_reserved;
sigc::signal<void, Vehicle &> signal_vehicle_added;
sigc::signal<void, Vehicle &> signal_vehicle_removed;
sigc::signal<void, Block &, Train *> signal_block_reserved;