USS developed the unique "Orinoco" system for their ore lines in Venezuela where they actally had to take loaded ore trains down a steep mountain. There is a second brake line from the locomotive that is valved into the release side of the brakes on each car. This allows a back pressure on the brake system to be set up from the locomotive, effectively giving continuous control of the retainers to the engineer. The brakes can be set and released from the locomotive while the train line remains fuly charged, and the normal and emergency function using the train line still works to set the brakes if needed.
This system is still used on the CN operations of the ex Missabe road.
Stories about reainers, exist and, are they necesarry?
Yes, , cause, but not often, the DB control circuit will trip and there's no dynamic braking, but if the air brake supplement the DB's when the ,circut breaker or some other problem, caused the failure, there's minimal time to increase the air brake app.to adequately control the train.
Then the brake pipe leakage increases the application and when the application is too much, brake recharge and release needs to happen. The retainers slowed the release,,. so, (no DB's) leakage, release and recharge, You've got to, with retainer slow the release during the recharge
Yes, retainers, "have got your back."
NS stopped and set retainers before descending Saluda until operations ceased in 2001. This is a training video from 1984 that describes the procedures to get a train safely down the mountain, combining dynamic braking with setting retainers.
cx500The delay while a conductor turns up the retainers on a specified number of cars at the top of the grade, and then a second stop to release them at the bottom, is incompatible with efficient operation.
Which is what led to the re-routing off Saluda.
You are right, there was no mars light on that trip. The memory was in error. Sorry judge.
Last time I looked (5 years ago ?), the Norfolk Southern timetable required the use of retainers on any train with a TPOB (Tons Per Operative Brake) over 125 [EDIT: various provisions are effective at 100 TPOB, and "Average (TPOB) must not exceed 140 tons" - see links below] going eastbound down "The Slide" (2.36%) from Gallitzin through Horseshoe Curve to Altoona. I'll see if I can find a reference to that.
- Paul North.
EDITED (and above): See this thread here from 2013 - "Start, Run and Stop": http://cs.trains.com/trn/f/111/t/221203.aspx?page=1
From one of my posts:
For trains descending "The Slide" - 1.1 miles of 2.36% from UN/AR to SF (almost Bennington Curve) - the table on pages 73 and 74 provide as follows:
That last restriction essentially precludes a solid unit train of 286,000 lb. = 143 ton cars from operating on this eastward Track 1 through the New Portage Tunnel ! (let alone very many of the 315,000 lb. cars)
From another one of my posts to the thread "Break checks @ Gallitzin, PA": http://cs.trains.com/trn/f/111/p/168584/1851570.aspx (emphasis added)
From pages 73 and 74, if a train's locomotives do not have the required number of dynamic braking axles andthe pressure-maintaining air brake feature - or in some other special circumstances - the air brake pressure 'retainers' on each car are required to be 'turned up' on the specified number of cars. That means the conductor would have to 'walk the train' for at least that many cars to do that - hence the train would have to be stopped for him/ her to perform that task.
See pages 73 and 74 of the August 4, 2008 NS Employee TimeTable ("ETT") Number 1 for the PITTSBURGH DIVISION, Northern Region, at this link - it mentions retainers in several places, typically when the dynamics are not working or would be 'overloaded' (no idea if that ETT is still in effect, though):
http://blet659.org/pbtt-1.pdf
- Last para. under 2. on pg. 73;
- 3rd and 4th paras. under 3. on pg. 74; and,
- 2nd. para. under 5. on pg. 74.
just an example of dynamics here
100 loads of frac sand 14000-15000 plus tons on a 1-almost 2% in some places with distributed power, newer big modern locos, i use a minimum reduction only with dynamics and the train behaves very nice. easy to handle, thats how good the dynamics work.
Legacy B&O passenger engines did not have MARS lights, however, in the late 60's until Amtrak, a number of former C&O engines were put on the B&O roster with B&O engine numbers - those former C&O engines did haver MARS lights. If the trip was truly in the 50's there were no MARS lights on B&O engine.
The mind, as we age, does funny things with our memories.
Never too old to have a happy childhood!
BaltACD Buslist Wonder who's power was on the point as B&O's didn't have Mars lights. What does a Mars light have to do with dynamic braking?
Buslist Wonder who's power was on the point as B&O's didn't have Mars lights.
Wonder who's power was on the point as B&O's didn't have Mars lights.
What does a Mars light have to do with dynamic braking?
The Mars light was in the OP description of the trip in which the retainers were used, they were not related to the retainers themselves. Reread the original post and you will find where the Mars light was mentioned.
Doug
May your flanges always stay BETWEEN the rails
The rail train lifting the rails on an abandoned CNR subdivision experienced unexpected train handling. On investigation the reason was identified. The encroaching shrubs and small trees were turning the levers and setting the retainers. While the crew never had to set retainers, for the rest of the program they periodically had to release them.
One thing to check for when stopped by a hot box detector for a hot box or hot wheel is the retainer. Once in a great while one will get turned to one of the retaining positions and cause the brakes to stick on. (Which is what they are supposed to do.)
Jeff
Maybe some of the current when in D/B goes thru Mars Light filaments on steep downgrades?
Thank You.
As has been stated by working railroaders elsewhere within this Forum, using dyanamic brakes instead of relying on retainers greatly reduces the expense of replaing brake shoes often. And improves train handling increasing smoother operation. Also stated elsewhere, all Amtrak road locomotives have dynamic brakes.
At least on my carrier - crews are not taught how to handle trains turning up and turning down retainers. They either have enough dynamic braking to decsend the grade or they wait until sufficient power with working dynamics are available to go down hill. A signifigant amount of our manned helper engines working time is assisting under dynamic braked trains down the various heavy grades.
Freight cars still have retaining valves. Dynamic brakes, however, have become much more powerful and more widespread so the actual use of retainers today is uncommon. The delay while a conductor turns up the retainers on a specified number of cars at the top of the grade, and then a second stop to release them at the bottom, is incompatible with efficient operation.
There may well be a few specific long steep grades with heavy tonnage where they are still regularly employed. Otherwise they are mostly a back-up system available if the dynamic brakes become inoperative for some reason.
Back in the 50's, while riding the B&O's National Limited from Washington DC to Cincinnati, while in West Virginia, the conductor came into the vestibule where I was looking out the Dutch Door and activated the retainer valve just before we started down a major grade. Back then, the Lawyers had not struck. Watching the train go through the night, the headlight and mars light shining ahead and with the light from the windows lighting the trees and the road bed plus the orange glow from the brakes and the sparks flying off the wheels was a sight not to be forgotten. I also have read about the requirement for freight trains having their retainers set up before descending grades. I know that retainers were to allow the train line to be recharged without releasing the brakes.
My question is do trains still have retainers and are they used or have dynamic braking systems and/or the newer feed valves that can maintain train line pressures eliminated their need?
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