Here are a couple more news links regarding the runaway:

(News Link 1)

(News Link 2)


There was a previous thread where it asked what the Orinoco brake system was. The following description is in a FRA report of a DMIR runaway in 1971:

"In addition, each car was equipped with an air brake system known as the "Orinoco" variable retainer. This system, used in conjunction with specially equipped locomotives, cars and cabooses, permits enginemen to retain full brake cylinder pressure on cars in a train when an application of the train automatic brake system is released, or to graduate such pressure as needed. The "Orinoco" systems were not in use on the train involved due to the caboose not being so equipped."

I had an idea what the actual Orinoco brake arrangement was, but had to find some more information before I stuck my foot in my mouth. There are some amazing claims as to what the Orinoco or automatic retainer systems are. An internet posting claims that Trains magazine did an article on the DMIR mini-quads and that they use a second brake cylinder. There was an early empty-load system that used two brake cylinders on the same lever in the triple valve era, but I hadn't heard anyone else doing this since or could see any real advantage compared to other arrangements. There is also a claim that Durango and Silverton now connects the retainer line to a second pipe which allows the engineer to release the brakes and recharge while retaining the brake cylinder pressure by controlling the exhaust of all brakes through a valve on the engine. I'm not sure if this is true, but the electro-pneumatic PS-68 system uses somewhat the same theory by using a magnet valve to control the brake cylinder exhaust but at each car (commuter use only). I recall claims that the ATSF York Canyon and DRGW/UP Kaiser coal trains also used an automatic retainer system. The name Orinoco comes from a mining railroad in Venezuela (Baldwin diesels now EMD) that had common ownership with DMIR, and Erie Mining is also supposed to use the system.

A cab photo shows the controlling mechanism. The second SA type brake valve is located to the left. My guess on the limited information available is that is is similar to an SA26 independent set for a maximum pressure of 25 psi (lighter spring? WABCO designation SA7?).

(Cab Photo Link)

As I suspected, this isn't anything new, just a new nickname for it. Westside Lumber used this same type of system that came on the skeleton cars they got from Swayne Lumber, Hutchinson Lumber/Feather River #3 (now Cass #11) had 6ET with a S3A for a similar system, no doubt there were many others. A mini-quad diagram in the 1976 DMIR rule book shows an AB-1 double check mounted on the AB pipe bracket connecting the brake cylinder and straight air line. While not actually controlling the retainer, the combined straight-air and automatic brake pipe system would enable either the use of the retainers in the normal manner or allow the straight air pipe to mimic the use of retainers with the engineer having a wider degree of control. (The double check valve arrangement results in the brake cylinder pressure being the higher of the pressure created by the control valve or the straight air pipe. 25 psi of straight air is approximately the same brake cylinder pressure resulting from a 10 pound brake pipe reduction from a charged auxiliary reservoir.)


Excerpts from the 1976 DMIR rule book:

(Definitions) Straight Air Retainer System: A system that performs the function of manual retainers except that the pressure retained in the brake cylinder is adjusted and controlled by the straight air brake valve in the cab of the controlling unit of the locomotive and and through a special arrangement on the cars so equipped.

Standard Brake Pipe Pressure - 90 psi; except 100 psi for ore trains without operative straight air from Highland to Two Harbors

Special Tests at Intermediate Locations

32. All trains handling ore not equipped with a properly functioning straight air retainer system or on which the engineer has not been qualified in the use of straight air retainers must stop at Highland. Enginemen must increase brake pipe reduction to at least twenty (20) pounds. Trainmen will inspect train to determine that brakes apply on each car. Train must not proceed until regulating valve setting is increased to one hundred (100) pounds and caboose auxiliary reservoir gauge shows pressure of not less than ninety-three (93) pounds.

33. Loaded trains running from Proctor to Missabe Jet., Duluth Docks or Steelton must not pass crest of the grade until a minimum of eighty-three (83) pounds is registered on the caboose auxiliary reservoir gauge.

Straight Air Retainer System Test

38. To ascertain that the straight air retainer system is operative, the following tests will be made:
(A) During prescribed air test and before releasing automatic brake application, crews will make a standing test of the system. Enginemen will make a twenty-five (25) pound application with the straight air valve and will ascertain from trainman that twenty (20) pounds registers on the caboose straight air gauge before releasing.
(B) Road trains will make a running test prior to arrival at Highland. At milepost N-45 enginemen will increase brake pipe pressure to ninety (90) pounds and ascertain that at least eighty-three (83) pounds registers on the caboose auxiliary reservoir gauge on the caboose before passing Highland. Enginemen will then make a twenty-five (25) pound application with the straight air valve and release same when trainman informs him that at least twenty (20) pounds has registered on the caboose straight air gauge.
(C) Trains operating through Proctor to Duluth Docks will make a running test through Proctor Yard. Enginemen will make a twenty-five (25) pound application with the straight air valve and will wait for the trainman to inform him when twenty (20) pounds registers on the caboose straight air gauge.
(D) If the prescribed straight air pressures cannot be attained, or the engineer has not been qualified in the use of straight air retainer system, the train must be stopped and manual retainers used in accordance with Rules 70 through 75.

39. At Waldo, it will not be necessary to stop if the brake pipe pressure registers at least eighty-three (83) pounds on the caboose auxiliary reservoir gauge.

Operation of Retainers

66. Before making air brake tests on trains of 150 cars or more originating at North End points, trainmen must turn up required number percentage of retainers in retarded release from the head end of the train. NOTE: On ore trains of less than 150 cars, the retarded release retainers need not be used unless requested by the engineer.

68. Except when straight air retainer equipment is provided and is operating properly, retainers must be turned up on loaded cars as follows:

MISSABE DIVISION
Road ore trains - 30% in retarded release
Proctor Hill and Steelton Hill Commercial Trains - 100% in high pressure position (Note 1)
Proctor Hill Ore Trains (Note 2) - 70% in high pressure and 30% in low pressure
Steelton Hill Ore Trains (Note 2) - 50% in high pressure and 50% in low pressure

IRON RANGE DIVISION
Road ore trains - 20% in retarded release
Highland to Waldo - Ore, Commercial and Ore Mixed - 75% in low pressure
Waldo to Two harbors - Ore, Commercial and Ore Mixed - 80% in high pressure and 20% in low pressure
Steelton Hill Ore Trains (Note 2) - 50% in high pressure and 50% in low pressure
Commercial Trains - Waldo to Two Harbors - 100% in high pressure position (Note 1)
Mariska Line (When dynamics are inoperative) - 50% in low pressure

Note 1: On commercial trains consisting of 70 cars or less with no more than 50% (35 cars) of the cars being loads, and with dynamic brake functioning on the locomotive, retainers need not be used from Highland to Two Harbors or on either Proctor or Steelton hills unless requested by the engineer.

Note 2: When handling foreign cars loaded with ore on Proctor or Steelton hills, all retainers on such cars must be set in the high position regardless of the location in the train.

71. When retainers are required from Waldo to Two Harbors, trains must stop and trainmen must properly position retainers and must not give signal to proceed until after the caboose auxiliary reservoir gauge shows pressure of not less than ninety-three (93) pounds.

Operation of Straight Air Retainer System

NOTE: The straight air retainer system is designed as a supplement to the standard automatic brake system and is found only on mini-quads and certain locomotives and cabooses. The straight air retainer system takes the place of conventional four-position retainers and must never be used by itself to stop a train.

When using the straight air system as retainers, the automatic brake should be applied first in an amount sufficient to control train speed. Then a straight air application can be made. The automatic brake may then be released. The advantages of making the automatic application first include a more rapid buildup of brake cylinder pressure and improved seating of packing cups in the brake cylinders in cold weather.

Brake cylinder pressure will be retained at the pressure registered on the straight air gauge, and brake pipe and auxiliary reservoir will be recharged to the setting of the regulating valve. Speed can be controlled by changing straight air pressures as dictated by running conditions. If a stop is to be made the automatic brake must be reapplied and the straight air released.

Another use of the straight air system is for de-icing brake shoes prior to descending grades.

73. Whenever a straight air retainer system is known to be functioning properly, the manual retainers will not be used.

74. The straight air retainer system must not be used unless the entire train is equipped with straight air retainer equipment and straight air hoses are coupled completely through the train. Straight air line angle cocks must be in the closed position on the leading end of the locomotive and the rear end of the caboose.

75. Should the straight air retainer system fail while descending Minntac, Proctor, Steelton or Highland to Two Harbors hills, the train must be stopped by a full service application or, if necessary, by an emergency application. When such a stop is made, retainers must be turned up as prescribed by Rule 68 before the brakes are released.

76. If straight air retainer system is restored, manual retainers need not be used and the straight air retainer system must be tested as prescribed in Rule 38 (A) before train proceeds.

77. The straight air system will not be used on Minntac, Proctor, Steelton or Highland to Two Harbors hills on any train of mini-quad cars when one or more cars in train are empty.

(End DMIR rules)


I do find it unusual that DMIR did not consider tons per operative brake or functioning axles of dynamic brake, and what type of dynamic brake the engine was equipped with. I'm not sure if DMIR had standardized on the four-position retainer or that just happened to be what their ore cars in use in 1976 were built with. I would also expect more actual rules or guidance regarding how the straight air retainer pressure should be varied. I wonder if the requirement for an equipped caboose was just to have access to the straight air pipe gauge?

The 1971 runaway involved 3 SD-9s, 15 loaded ore cars and a caboose, and under normal conditions the dynamics and a light brake application would be sufficient. The engineer did not make an emergency brake application until the train reached 50+ mph though the maximum speed was 20 mph. Not thinking he got a full emergency brake application, he released the air, recharged and made a second emergency brake application. The train struck empty cars on the Duluth ore dock. The conductor and flagman uncoupled the caboose but closed the angle cock on the train first. The caboose stopped, and then they coasted the caboose down the hill picking up the head brakeman who had jumped. The engineer jumped with minor injuries, the fireman died in the collision, the head brakeman, despite having survived jumping, died of heart problems after walking to an ambulance. The FRA determined the causes were weather (-29 degrees), the failure to use retainers as required by the rules (70% on high pressure and 30% on low pressure), not fully charging the train before descending the grade and a loose wire in the dynamic field loop circuit that reduced dynamic brake effort to an estimated 20% of normal. Apparently the only reason they were not using the Orinoco system that day was because the rules required the caboose to be equipped to verify the straight air pressure. The rules are also vague on any restrictions on handling the straight air in regards to slack control.

In 2010 there was a head-on collision between two ore trains near Two Harbors blamed on inadequate crew communication, failure to observe an "after arrival of" on the track authority and an engineer using his cell phone. There were injuries to all five crew members.

CN has been called before on changing operating practices on properties they have acquired. In 2006 there was a runaway on the old BCR that killed two of the three crew members. The train consisted of one GP40-2W and one loaded centerbeam. Cause was determined to be a combination of the improper design and maintenance of the car resulting in less than required braking effort, outdated brake shoe specifications, the assignment of a non-dyanmic brake equipped unit and management's failure to consider the operational requirements in changing the type of engine assigned and related rules.

The attorney's claims are questionable, but the motives are obvious. DMIR ran trains for a century in below-zero weather, and more time without dynamics than with them. The operating conditions are nothing new, but cold weather, snow, ice and poor rail conditions do degrade braking capability. I can imagine that if CN hadn't run a spreader that the crew would have had difficulty walking the train for an air test or to turn up retainers in three feet of snow plus the berm along the track. Based on the engine consist, I doubt the Orinoco brake is being used. Based on the 1976 rule book, the brake pipe pressure should have been increased to 100 psi and 80% retainers used in the high pressure position and 20% in low pressure (slow direct with current type of retainers). Newer cars with empty-load would be advantageous, but under severe conditions would not replace retainer use.

Did CN stop using the straight air retainer system? Had the rules for using retainers been relaxed or eliminated? Was the snow and ice the actual cause? Why hasn't the use of a rear DPU been instituted to take advantage of the additional air brake control and recharging?