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Run 8 Train Brakes for Dummies

Freight Train Brakes for Dummies 101

Locomotive Terminology

BC Brake Cylinder PSI: The amount of pressure applied to the locomotive's brake cylinders in PSI.
BP Brake Pipe PSI: The current PSI of the locomotive's Brake Pipe.
EQ Equalizing Reservoir: A small reservoir used on locomotives to regulate the Brake Pipe.
Train Brake (aka Automatic Brake): The main airbrakes for the entire train, including the locomotive. Regulated by the Brake Pipe.
Independent Brake (aka Indy Brake): The locomotive's airbrakes can be controlled by the engineer independent of the Train Brakes.
Slack: The free-play between couplers (usually about 2" to 4" per coupling), and adds-up big time on long trains. 100 Cars * 2 to 4 inches per car = 200 to 400 inches of slack = between 17 and 34 feet of slack on a 100-car train. Run that slack out too hard and SNAP goes a coupler. Bunch that slack up too hard and you'll derail a car right out of the train.

Train Brake (also known as Automatic Brake)

Each unit in a train, whether locomotive or car, has its own Brake Pipe, and when units are coupled together, their air hoses are joined which joins their brake pipes. Ergo, after all units are coupled into a train, there is one very long contiguous Brake Pipe. This pipe supplies air to each unit's Triple Valve, and this valve senses air pressure variations between the Brake Pipe and the unit's own reservoirs, causing the brakes to either apply or release. If the Brake Pipe PSI falls below the unit's reservoirs, the Triple Valve applies air pressure to the unit's brake cylinders at a rate proportional to the brake pipe PSI difference. When the brake pipe PSI equals the car's reservoirs, the system holds. If the Brake Pipe PSI rises above the unit's reservoirs, the brakes release fully.

When the Engineer wishes to apply the Train Brakes, he makes a certain PSI reduction on his Equalizing Reservoir. This EQ regulates the brake pipe, causing the brake pipe to begin releasing air at the engineer's control stand. This is why you hear air escaping when you make a train brake application. As the locomotive's brake pipe pressure falls, so does the rest of the train. HOWEVER, and this is important: The Brake Pipe PSI is being reduced at the control stand, and this pipe could be a mile or more long. It takes time for the BP to reduce throughout the entire train. This means that during brake application, the pressure at the front of the brake pipe will be lower than the pressure at the rear of the brake pipe (the end of the train). This means that the brakes will start setting first on the units closest to the engineer, and progress rearward as the pipe's air escapes towards the front of the train. This is why if you have your EOT set, you will notice that the EOT's brake pipe reading will always lag behind what the engineer sets. Since the brakes at the front of the train start setting sooner than the rear, the slack will want to run-in (or bunch).

When the Engineer wishes to release the Train Brakes, he sets the EQ back to full PSI (90psi usually). Now the EQ is higher than the BP. This causes the locomotive's air system (Main Reservoir) to start recharging the Brake Pipe, and the compressors come on. But, as above, the locomotives are charging the brake pipe from the front, meaning the BP pressure will be higher than at the rear of the train. This means that the train brakes will release at the front and progress rearwards along the train. If the locomotives are pulling, the slack will run-out (or stretch the train).

Worst-Case Scenario: You are on level track and have set your train brakes to slow down for a red signal, and you have slowed your mile-long freight to a few MPH when your signal clears. Your train's slack is bunched-up. You see your signal clear to green. Do you then release the train brakes and start pulling hard? NO NO NO! You'll break your train in two. At such slow speeds, if you apply throttle and release the train brakes, the front cars will release and the release progresses rearwards, but as your front cars release, the locomotives pull hard against them, jerking them forward. Jerk at the right part of the train where the brakes haven't yet released fully and SNAP! You've broken a coupler. In this scenario, it's best to complete your stop, then restart the train gently. The above also applies if you're in the same scenario but have your slack stretched. Due to the fact that the front brakes release first and progress rearwards, you still run the risk of overstressing a coupler when speed is low and locomotive tractive-effort is at it's highest.

Independent Brake (Indy Brake or Locomotive Brake)

The engineer uses the Brake Pipe to control the air brakes on the entire train, including the locomotives. However, he can also control the locomotive brakes independently of the rest of the train. He can cause the locomotive brakes to apply harder or softer than the rest of the train in order to control slack with the locomotives. When stretch-braking, the engineer would set the air on the train, but bail-off the brakes on the locomotives so as to keep their brakes released and the train brakes applied. This causes the train to want to stretch out, which is desireable in certain circumstances. If he wants to bunch-up the train, he would cause the locomotive brakes to apply harder than the rest of the train. He can directly control the PSI applied to the brake cylinders of the locomotives.

If the engineer does nothing with the independent brakes, they will simply follow what the rest of the airbrakes are doing, until he either bails-off the independents OR sets them to a higher setting.

Well, that's all well and good John, but what do I do with this fountain of knowledge?
Glad you asked.


The idea here is to gently stretch the train (if it's not already) whilst accelerating.
Make sure Locomotive Brakes (Indy Brakes) are applied full
Release the Train Brakes
When the train brakes have all released (you'll notice this when the EOT Rear PSI begins rising), place throttle into Run1 or Run2 (if needed) and gently feather off the indy brakes to control locomotive surge.
As speed increases and amps decrease (amps = tractive effort), advance the throttle one notch at a time.


This assumes you are stopped with the train brakes applied, and the Indy Brakes applied to full.
Place Throttle in Run1 or Run2 (if needed, and on the steep sections of Tehachapi, Run2 will usually be needed)
Apply Sanders if necessary (I'd do it anyway jsut to be safe).
Release the Train Brakes (LEAVE INDY BRAKES APPLIED FULL!)
As the train brakes release from front towards the rear, the train may begin rolling forward.
If not, apply Run3. Gently and I mean GENTLY begin feathering-off the INDY brakes little by little
Keep gently reducing the Indy Brakes as the train begins accelerating
Once the indy brakes are released fully and speed is increasing and amps decreasing, advance the throttle to the next setting.
Rinse and Repeat.


The easiest of all the scenarios.
Apply Full Independent Brakes
Release Train Brakes, allow slack to adjust.
Begin releasing the indy brakes and allow the train to roll, keep the train bunched though.
Activate your dynamic brakes if continuing downgrade.


The idea here is to stop the train with the slack stretched out, which it should already be stretched. Depending on how steep the grade is, you may be able to simply stall the train and apply the Indy Brakes to hold the hill once stalled. If it's a steep grade, you'll also need to apply the train brakes as well. You DO NOT want to stall the train in too high a throttle setting, as you risk breaking a coupler. Run2, perhaps Run3 if absolutely necessary should be the max to stall the train properly.
Begin reducing the throttle notch by notch, allowing speed to reduce towards stall (Run2 or lower usually).
If grade is shallow enough, or train light enough, allow train to stall, and as speed approaches zero, begin applying the indy brakes (KEEP THROTTLE APPLIED).
Once indy brakes are set full, Reduce any remaining throttle to idle notch by notch, observing if your train will want to roll back at all. (NOTE: in Run8, you may notice some roll-back as the couplers have to be modeled in physics as very large springs. Once the couplers "unload" a bit, the rollback should stop. Using too much throttle at stall exacerbates this rollback).
If Grade is too steep, or train too heavy, as train speed approaches zero, begin applying train brakes as well, a 6 to 10 psi set should be sufficient.

NOTE: If the train brakes are needed to hold the train on
the grade, make a brake pipe reduction as the train stops or
just before it stops.


The idea here is to stop with the slack bunched (or "run-in").
If in power, gradually reduce the throttle to IDLE and allow the slack to bunch.
Gradually apply the independent brake to bunch slack further.
At a sufficient distance from the stop, make a brake pipe reduction and use the locomotive brake to keep the slack bunched.
As the train comes to a stop, make a final brake pipe reduction and allow the locomotive brakes to apply.

NOTE: You may use the dynamic brake to bunch slack if
available. However, as speed drops below the dynamic brake
range, supplement with the independent brake.

-Individual couplers can now be selected by going in between the cars and selecting the desired coupler. You might have to move the mouse around a bit. When a coupler is selected, the entire unit turns red for now and a Coupler Options window pops up. The EOT is assigned this way now.

-Uncoupling: Uncoupling is now accomplished by selecting one of the two couplers and pressing the "Open Coupler" button at the top of the Coupler Options window. This button simulates a trainman actuating the coupler-pin lever that unlocks the coupler and you'll hear the sound of the lever being pulled. Once one of the two couplers is opened and the rest of the train pulled away a sufficient distance to separate the airhoses, you'll hear the uncoupling sound and the air escaping.

-ANGLECOCKS: Run8 now simulates AngleCocks. These are valves on the brakepipe at each end of the car, and in Run8, they are associated with the couplers. When a coupler is selected, you'll see buttons for Opening and Closing the anglecock at that coupler. PAY CLOSE ATTENTION to your use of these anglecocks, or you'll dump all your air by accident. Before uncoupling, close the anglecock on the coupler that stays with your train. When you desire to couple onto some units, it's safe to make sure your anglecock is closed, then couple onto the units, then open the anglecocks on both of the couplers that have just been coupled.

NOTE: After a coupling event happens, the anglecocks should automatically set themselves as a convenience to you.

If one or both anglecocks are closed at a coupling, you'll only have airbrakes to that point since the brakepipe is closed off at that point. Under normal circumstances, if you set your EOT at the very end of your train and perform an airbrake test by setting 6 to 10 psi of air, you should eventually see the Rear brakepipe reading start to drop after several seconds. If it never drops, you have a closed anglecock somewhere in the train.

If you accidently open one of the anglecocks at either end of your train, you WILL dump the air, which puts the train in Emergency mode. Shame on you. Don't do that. Close the offending anglecock (you'll know it because it will make a loud hissing sound of air escaping), and follow the prompts on the MFD screen to reset your trainbrake system. Throttle must be at Idle, and Reverser set to Neutral in order for the PCS Cutout Relay to reset.

(Cheat: After resetting the PCS Cutout, press F7 to speed up the brakepipe recharge. This will magically increase your BrakePipe pressure to a higher level, thus reducing the wait for the impatient. If you press F7 and the pressure does not come up, then you have not cycled the brake lever properly, or you still have an anglecock open in a naughty location).

Run 8 User Help Introduction - Tips, Tricks, and Known Issues - Performance Options - Run 8 Default Key Chart

Run 8 and Your RailDriver Controller - MFD Manual - Train Brakes for Dummies - Hosting a Multiplayer Session