Moving Ore Downhill

The Missabe's worst grade was the 2.2 percent descent from its ore sorting yards at Proctor, 7.7 miles to the Duluth Ore Docks.  They set retainers on a portion of the train based on a table in the rules book.

The train's power is/was only on the front, with up to 110 cars.  In the steam era, the loco ran backwards.

In the pre-radio days, the conductor would start dumping air from his end (the caboose) if he judged the train was moving too fast.

Milt pretty much nailed it on

Milt pretty much nailed it on that one. In modern times you may see some distributed power on the rear end, but honestly what he said about the retainer valves pretty much sums it up. The engineer has to be very careful about not using up all the air brake pressure or you'll get a runaway like has happened at Cajon Pass so many times. I can just hear the dynamic brakes screaming....

Location

Power on the point.

Unless the railroad has remote control or DPU they probably wouldn't have power on the rear.

Helpers

If you needed helpers on the way up, now adays, many places leave them attached on the way down for added dynamics.  Midtrain or rear end.

Head end

Since the entire train wold be descending the grade, the slack should remain bunched.  Modern practice would be to have the locomotives on the head end, using dynamic braking if possible, or perhaps a combination of dynamic and air brakes.  As has been said, if the train had helpers of DP (distributed power) units then they would likely (maybe, in the case of helpers, definitely in the case of DP) be assisting in braking as well.

Depending on the grade, the tonnage, and the situation, there is a possibility that an engineer who was using air brakes alone might have to pull the slack out, pulling against the brakes without releasing them.  This could be because a section of the grade is not as steep, and the braking force needed elsewhere would stop the train on that portion, or because he for whatever reason used more air than was needed to control the speed.  I have seen this happen in situations where some braking is needed, but the minimum reduction which will allow a running release (releasing without stopping the train) is too much and will unduly slow or stop the train.  Still, in all these situations, the locomotives would be on the head end - just thought some prototypical considerations might be interesting.

Way back, in the days before air brakes and knuckle couplers, It was common to see logging and mining lines on heavy grades position the locomotives at the bottom of the grade at all times.  That way, there was no risk of a coupling braking and cars running away from the train.  While I assume it was done to some extent on main lines as well, I doubt it was as common except in locations where the entire trip was on a heavy grade.  So even here, trains would likely have engines on the head end, meaning downhill end on a train descending a grade.

Thus, with very few exceptions, I'd put the engines on the front of a train, and let the enigneer figure out the best way to control the train.

In the 1880s & 90s

The train would be inspected by the crew and car inspectors at the station at the top of the grade.  The crew would set all of the retainers.  By the ETT Special Instructions you could only have one car without air brakes for every four cars with air brakes.  All of the air brake equipped cars would be behind the engine and the cars without air brakes would be at the end of the train.  The brakemen would all be "decorating" the car tops with each brakeman responsible for four cars.  When the engineer whistled for brakes, they would tighten down the brakes on their four cars and then be prepared to tighten them down again when the engineer whistled for brakes again.  When the train reached the bottom of the grade it would stop to cool the wheels, release all the retainer valves and unwind the brake wheels.

Modern days

Here is a video on my layout of a train descending a 4% grade. I also run trains with a rear DPU, the area I model has done both ways. Spreading the locos through the train reduces the forces trying to derail it. I don't need the locos for the descent but do require the power for the climbs.

Mike Ruby

thanks

thanks for all the comments guys! great info!

Fewer air brakes in the 1880's

The crews would most likely set the brakes.  I doubt there would be many retainers used since very few cars in the 1880's had air brakes (according to White, only 8% of the US fleet had air brakes in 1889). 

By the 1890's there would be more air brakes.