This stamp shows a locomotive used to transport both people and mail in its day.
This parcel post stamp shows a steel plant.
This parcel post stamp shows a mail train, presumably carrying parcels.
This parcel post stamp shows a railway postal clerk collecting parcels.
This coil stamp shows a caboose from the 1890s. It is part of the Transportation Coils series and is perforated 10 vertically. It is intended for bulk rate mail. This particular stamp is also a precancel from Vandalia, Ohio. (I need to retake this picture so the stamp s orientated correctly.)