Sorry....Should have elaborated just a bit on a Construc. A typical passenger construc was the loco/tender followed by a general purpose car, sometimes carrying "hot" freight and excess baggage, a mail car, baggage car, passenger car/sleeper, passenger car/sleeper, dining car, passenger car, passenger car, observation/bar car. On freight trains the construc was determined by destination, load, weight, type of car, and a few other factors. The total weight of the train determined the power used and if extra power was needed and when (grades). The total weight is known as "Weight on the Drivers" and the type of power and weight on the drivers in conjunction with time/distance, determined how much money the engine crew was paid.

Even after the advent of diesels this formula was still used. So if you drew an underpowered, slow, heavy freight, you weren't going to make as much money. On my Dad's run on the Pennsy between Columbus, Ohio and Pittsburgh (Pitcairn or Conway yards), the worst scheduled freight was "CP-6" which was always slow going. The best scheduled freight was "CG-8" which was generall about 90 cars, 4 to 6 diesels and ran at the track limit ("CG-8, never late"). In the days of the 16 hour outlaw, it wasn't uncommon for Dad to outlaw before he even crossed the river on CP-6 and conversely, he'd be home a lot faster if he drew CG-8 and PS-10 on the return.

Spaw