if event.type == "train" then
  local rc = get_rc()
  if rc:find("d23a_unload") ~= nil then
    rc = rc:gsub("d23a_unload", "d23a_load")
  elseif rc:find("d23a_load") ~= nil then
    rc = rc:gsub("d23a_load", "d23a_leave")
  end
  set_rc(rc)
end