One or more barges or other floating vessels, in charge of a self-propelled vessel which has undertaken to transport such responsibilities elsewhere. A tow is made up when it has been hitched together and made ready for moving. A barge moored to the front of a towing steamer is the tow barge and the ones out in front are the lead barges and when a barge is towed alongside a towboat it is "slung under her arm". When pulled behind, as sometimes is done in times of floating ice, the barges are said to be "railroaded".