"Setting a retainer"

[kenneo]

MODELCAR .... The reason for the use of retainers is to control the speed of the train and permit the train to recover its air so that it can stop properly and control the speed properly.

Dynamic brake usually does this quite well.

When the weight of the train exceed the alowable dynamic brake capacity (will be stated in the Timetable, Special Instructions for each district or grade), then the air must be used in adition to the dynamic

Depending on the specific conditions, the engineer may be able to make the proper reductions and while the brakes are released, there can be time for the system to equalize prior to the next reduction. In such cases, no retainers would be used - only the automatic, and you would get smoke from every wheel.

The amount of reduction and its duration also dictate whether or not retainers will need to be used.

To illustrate: one grade I have worked on has, from the top, descending, 2 miles of 3.3%, 2 miles of 2.75% and 4 miles of 1.8%, 2 miles of .5% ascending and almost 5 miles of 1.8% descending. The Special Instructions permit no more than 30 Axels of operable dyanimic brake for 1st generation units and 18 Axels of operable dynaimic brake for any engine consist that has Extended Range dyanimics operable (even if it is only 1 axel of ERDB).

If the engineer can control the speed with the dynamic only, then no air will be applied. If air is needed for the 3.3% part, than the engineer probably won't use retainers but stay with the automatic and release the brakes byond the 3.3% portion.

But if the train is of such a weight that the engineer must use the air on the 3.3% and the 2.75%, he may have the retainers turned up or not (his/her choice) but would have to stop for 15 minutes at the end of the 2.75% to cool the wheels.

Should the engineer need air the entire length of the grade, then he would have the retainers turned up at the top (the Special Instructions will give the applicable formula for the grade in question), turning up only the minimum, and only on every other car starting from the rear forward. At the intervals stated in the Timetable Special Instructions, the engineer will stop for the required 15 minutes at the required points and the retainers that were being used will be turned down and the retainers that had not been used will be turned up (thus using "cold" wheels - the hotter the wheel gets the less braking power it has).

If the engineer must use retainers on more than 1/2 of the operable brakes in the train, then he must remain stopped for 30 minutes for wheel cooling to allow ALL of the wheels to get "cold".

Like some of us have been saying in this thread, when and where you use retainers has a lot of variables, and without writing a 3,000 word article about how to do it under all circumstances, please accept our generalized statements. We are not trying to mislead -- we are trying to answer truthfully and not to confuse the issue with an excess of information.

[Murphy Siding]

kenneo: Did those trains we've all seen in pictures, hauling coal down some mountain in PA or WV, with all the blue smoke from the brakeshoes have to stop at some point and let the wheels cool down?

Thanks

[Modelcar]

Eric: Thanks for the list of data you provided in examples and I'm sure from experience in doing some of the mentioned processes. Seems the engineer has quite a bit resting on his shoulders upon making decisions at the summit how he is going to control his train down the hill in front of him.....I would think he must feel a great bit better if he has...say 5 6-axle engines with good working dynamics to draw from.....Retainers or not...ha.

[beaulieu]

The key factor in whether a train needs to set retainers is "Tons per Operative Brake". On most railroads anything over 100 tons per operative brake will require retainers to be set.
Another factor can be effective axles of dynamic braking, there is a limit on how many locomotives in one consist can be in dynamic braking. Too many and the train can do the opposite of stringlining. This is why you will see up to four helpers on the rear of loaded coal trains descending though Horseshoe Curve. Normally with enough working dynamic brakes there are only a few grades in this country that require retainers to be set when operating heavy bulk trains. All of them have gradients of 2.5 percent or higher with a single exception. They are Cajon Pass (south track), Raton Pass, Soldier Summit east slope, Cima Hill, Blue Mtns, and Saluda Mtn. Cima Hill is the only gradient that isn't over 2.5 percent. It is also the location where the North American speed record for a loaded freight train was set, when a loaded welded rail train lost its brakes on the west slope. The speed recorder logged a speed of 115 mph. but based on signal block logs estimated speed upon derailing was 130 mph. It is a straight shot from top to bottom with a curve at the bottom. The Blue Mountains on the UP in Oregon are the only grades where retainers are needed very often, with the introduction of DPU they probably are too common there anymore either.

[Modelcar]

....Interesting info....Are you saying if too much resistence is used up front as in dynamics the weight of the trailing cars would buckle them off the track to derailment...?

[kenneo]

QUOTE: Originally posted by Murphy Siding

kenneo: Did those trains we've all seen in pictures, hauling coal down some mountain in PA or WV, with all the blue smoke from the brakeshoes have to stop at some point and let the wheels cool down?

Thanks

Depends on how long the brakes needed to be set. Some of those spurs were short enough to no need wheel cooling stops.

[kenneo]

QUOTE: Originally posted by Modelcar

Eric: Thanks for the list of data you provided in examples and I'm sure from experience in doing some of the mentioned processes. Seems the engineer has quite a bit resting on his shoulders upon making decisions at the summit how he is going to control his train down the hill in front of him.....I would think he must feel a great bit better if he has...say 5 6-axle engines with good working dynamics to draw from.....Retainers or not...ha.

Yes, all those axels are a comfort. There are a set of rules and formuli that the engineer uses to make his decision. The road I worked for made it real easy. Divide the gross tonnage of the train by the number of brakes that are working (usually, all of them). Compare that resultant number to the entry in the Special Instruction for the use of retainers and if you have a bigger number for your train, you turn them up. If not, dynamics away down the hill.

[kenneo]

QUOTE: Originally posted by Modelcar

....Interesting info....Are you saying if too much resistence is used up front as in dynamics the weight of the trailing cars would buckle them off the track to derailment...?

Absolutely. Without fail.

[markpierce]

Get real guys! In the steam era, a train might have a half dozen brakemen or so on steep downgrades to handle the braking. Now, a train might have two crew members who aren't "walking on the rolling stock setting retainers", and definitely no caboose. Diesels' dynamic brakes revolutionized down-grade railroad practices for the last half century. Also, on the "uphill" no more time watering several locomotives spaced throughout a train. Yes...the "good old days" are great for modeling, but if you are a "real" railroader (especially a brakeman), would you want those days?

[Modelcar]

markpierce....You aren't saying that retainers aren't used at all any more are you...? There evidently are places that require the train to stop on summit and set retainers....I know that was the circumstance down in NC at Saluda before rail operations were haulted on that line roughly 4 years ago.....

[GP40-2]

Modelcar, setting retainers was mandatory on many of the B&O subdivisions in Western PA and W.VA for trains above certain tonnage. Of course, the advent of MU diesels with extended range dynamic brakes pretty much stopped the need to set retainers on a routine basis. Some grades that come to mind as having mandatory retainer settings were the Sand Patch Grade, the grades on the West End in MD and W.VA., the sub up to Somerset, and the Streets Run Grade out of Pittsburgh and the long grade from West Alexander PA down down to Wheeling W.VA on the Wheeling-Pittsburgh Subdivision. (There were more, but those come to mind)

[mackb4]

At one time we was allowed to use retainers when flood loading a coal train on a grade.But then some wisbang said not to.I liked them because on a 100 car train the conductor would set 15 retainers and no handbrakes while loading.Then all you had to do when you got ready to leave is draw the brakes(auotmatic) down real good and let the duct.turn the retainers back.Knock the air brakes off,and away you go.

[Modelcar]

....GP40-2.....Curious of setting retainers on the Somerset sub....{the S&C}...my home was just one mile from that line at Kantner, Pa, {Stoystown}.....Where would they have set retainers on that line....The loaded run was upgrade from down near Johnstown to Somerset and I wasn't aware of a steep grade {down}, from Somerset to Rockwood.......

[Modelcar]

mackb4...can you explain that a bit more...for us layman....

[jimrice4449]

The only time I touched a retainer as a brakeman was working the BN job from Kettle Falls Wa to Nelson BC. We would lay over in Salmo BC leaving the train on the main. One night some clowns set the retainers on a couple of flats of lumber and when we figured out why we wern't runinning as we should the next day, I got to walk back and kick them off.

[GP40-2]

Modelcar, Now that I think about it, I was thinking about the old FM&P sub that ran down through Uniontown, not the Somerset sub...Somewhere in my left over B&O paperwork, I have a operating rule book from the late 70's-early 80's that lists every grade on the old Pennsylvania Divsion that required retainers.

[SooHoghead]

When I was a Brakeman on the GN Mesabi Division, Superior, WI in the 60's, retainers were used on the loaded ore trains. (205 ore cars) Even with dynamic braking, a lot of the Engineers requested that 50 retainers be set on the head-end, in the SD position as an aid to keeping the slack bunched when a brake pipe reduction was restored to the operating pressure. (usually 75psi)  SD stands for Slow Direct. SD position released the pressure in the cylinder portion thru a small orface, which extended the time the brake was applied on the car.

Positions of a four position retainer valve as follows-

D   -  Direct (Handle in a straight down position)  Exhausts normally.

SD  - Slow Direct (Handle in a 135 degree counter clockwise position from straight down)

HP  - High Pressure (Handle in a 90 degree counter clockwise position from straight down) Retains 20 psi in brake cylinder until retainer is returned to Direct Release, or SD position. Does not retain pressure until a brake application is applied.

LP -  Low Pressure.  (Handle in a 45 degree counter clockwise position from straight down) Retains 10 psi in brake cylinder until retainer is returned to Direct Release, or SD position.  Does not retain pressure until a brake application is applied.

One interesting notation - Brake cylinder was only required to maintain pressure for five minutes during an initial air test.  In reality, some would hold pressure for days.

Later on the Soo Line as an Engineer we were required to use retainer on the White Pine Line. At White Pine there was a small yard with a derail at the far end and an extension of about five hundred feet of track with a bumper at the end.  The intresting part was that the bumper was at the center of the base of a five hundred foot tall smoke stack. Oops. The smoke stack is still there undamaged even though no-one ever used the retainers. Jack

[CShaveRR]

I never dealt with retainers in my years as a yard brakeman, except for maybe releasing one that kept a car from rolling into the clear.  But I do remember the days when the retainers were up by the brake wheels...and I mean, up!  One either carried a pole with him to help set the retainers, or had to climb up and over to adjust the valves.