Iowa Code § 617.4: Consolidated railways.

If the action is against any railway corporation which has sold or leased its property and franchises to any other railway corporation as authorized by section 327E.2, service of the original notice may be made upon any station, ticket, or other agent of the merged, vendee, or lessee corporation in the county where the action is brought; if there is no such agent in said county, then service may be made upon such agent or person in any other county.