Australian model trains - Model Railroader Magazine

In the early days of diesels of only 1500 HP and limited TE, it was a given that two, three or more would be needed for mainline trains. So cabless units and fixed or semi fixed loco consists made sense. As HP/TE grew, but before train weights grew to todays levels, the usefullness of cabless boosters declined, and as hood units replaced cab units, railroads moved away from boosters.