switch (FEAT_TRAINS, SELF, unicorn_resting_cost2, [
  var[0xB4, 0, 0xFFFF]
]) {
  0:       return 100; // cost when waiting for no reason
  1..30:   return 50; // cost when driving very slow/accelerating/beaking
  default: return 0; // normal operation
}

switch (FEAT_TRAINS, SELF, unicorn_resting_cost, [
  var[0x8A, 0, 0x0F] | (var[0xB2, 1, 0x01] << 4)
]) {
  0x02:       return 10;  // cost when vehicle is loading/unloading 
  0x10..0x1F: return 10;  // cost when vehicle is stopped
  default: unicorn_resting_cost2;
}

item(...) {
  ...
  graphics {
    running_cost_factor: unicorn_resting_cost;
  }
}