DPU trains (was Re: Thunder on Blue Ridge)

[NW Mailing List]

I have seen DPUs in use over the last several years on BNSF, KCS, AND UP.  DPUs have been used over NS from Memphis to GA on Powder River Coal trains by way for at least 8 years.  ON BNSF through NM and AZ it's common to see DPU's mid-train and on the rear (intermodal-mixed freight-or bulk load trains).  Many BNSF-KCS Powder River coal trains that running over the KCS that I photograph in Oklahoma and Arkansas have mid and rear end DPUs. I've seen as many as 9 units total on trains.  It's a sight to watch a loaded Powder River Coal train with 7 to 9 units (head-mid-rear) attack Rich Mountain on the KCS! 

Unless I'm crazy......(always possible) during the summer of 2009 (the week of the NWHS Convention) I photographed a train with a DPU (single unit on the rear end) west of Bluefield on an eastbound time freight.  The train had locomotive problems and stopped with the head-end at Switchback just short of the Mayberry Bridge. I had a chat with the crew about their use of a DPU and problems with an ex-CR SD-60 that was their second unit back from the head-end. Later that week in talking with Virginia Division crews I was told that DPUs would be used on coal trains over the Whitethorn District eliminating the manned pusher that had always been stationed at Whitethorn.  

It was interesting while I was in Pittsburgh last week (I flew up Sunday morning so I could spend some time shooting trains during the afternoon) that none of the 10+ trains I saw and or shot at locations both east and west of Conway had DPUs. 

As for unmanned locomotives.....I would think that DPUs could be considered either manned or remote (semantics) depending on how you choose to look at it.  Are mid-train or rear end DPUs any more remote than the 2nd, 3rd, or 4th units of a 4 unit head-end consist with the crew operating from the lead unit?  It's all one entity controlled by a crew located on the train; locomotives (wherever located) and cars coupled together as a unit. It's not like a remotely operated locomotive switching cars in a yard. 

Ed Painter from Narrows, VA currently living in Russellville, AR 




Here's some history, technical , and operating information on the use of DPUs from Wikipedia:

Where operational considerations or economics require it, trains can be made longer if intermediate locomotives are inserted in the train and remotely controlled from the leading locomotive. Distributed power is a rail transport term for this concept. It describes the physical distribution throughout the length of a train of separate motive power groups. Such 'groups' may be single units or multiple consists.[1]

Advantages and disadvantages The obvious benefit is reducing drawbar pull on the front cars of a train versus what would be required if all the power exerted were at the head end. On an undulating track profile, a skillful driver can manipulate the relative power outputs (as well as dynamic and air brake applications) to minimize run-in and run-out of the coupler slack throughout the train."[2]

This reduced drawbar pull will reduce the lateral force between wheel and rail on curves, thus minimizing wear on various components. Lower friction results in fuel savings and/or the capability of running heavier trains.

Another benefit is quicker application of standard air brakes. It can take several seconds for brake-pipe pressure changes initiated by the driver to propagate to the rear of the train with all braking control at the front on a conventional train. When distributed-power locomotives are directed to set the brakes simultaneously, the desired air pressure change will reach more cars sooner. This is particularly true when the extra power units are in the middle of the train.

The main disadvantage, especially with mid-train units, is the time and track configuration required to add and remove additional locomotive consists. There are costs associated with equipping locomotives with the extra control apparatus. Operationally, loss of the telemetry signals is coped with in various fail-safe manners.

History Since the 1960s, railroad distributed power technology has been dominated by one company, Harris Controls (originally Harris Corporation-Controls and Composition Division, later purchased by General Electric, and now known as GE Transportation Systems Global Signaling), who have manufactured and marketed a patented radio-control system known as Locotrol that is the predominant (perhaps only?) wireless distributed power system in use today around the world.

With its origins in the early days of SCADA technology for the remote control of pipelines and electric utilities, and from an early concept of Southern Railway President, D.W. Brosnan, Locotrol was a product of the North Electric Company (Galion, OH) which was later purchased by Radiation Inc.(Melbourne, FL) and--in turn--purchased by Harris Corporation (also headquartered in Melbourne, FL), and was first tested on the Southern Railway in 1963. The first production Locotrol was installed on the Southern Railway in 1965.

In the early years of this technology, Wabco also had-for a relatively brief period-a competing system called 'RMU' (Remote Multiple Uniter) which was installed on a few North American railroads. However this system did not prevail and soon went out of production. Prior to the advent by North Electric of the proprietry 'LOCOTROL' name, the product was referred to as 'RCE' (Radio Controlled Equipment) or 'RCS' (Radio Control System) and the Lead and Remote units as 'master' and 'slave'. The colloquial 'master' and 'slave' terms, though, were not formally used by the manufacturer. In some U.S. railroad parlance Locotrol trains are referred to as 'radio trains'.

Technology A locomotive that has been fitted with Locotrol DP equipment may be set up as either a Lead or Remote 'active' unit; the Lead unit being the controlling locomotive. Only one distributed power-equipped locomotive in any Lead or Remote consist (group) is active. Other locomotives MU-coupled to this 'active' unit operate conventionally as multiple units.

There are two basic modes for over-the-road distributed power operation. Locomotive control can be synchronous (MU), whereby control commands made by the driver in the Lead unit are transmitted instantly via radio telemetry to-and are followed immediately by-all Remote units in the train, or independent whereby the driver may set up and independently operate the Remote locomotives as a 'front' and a 'back' group (or with Locotrol III and subsequent versions; as 'Lead', 'Remote-forward', Remote-intermediate', 'Remote-rear', and 'Remote-trail' groups-this latter at the rear of the train). The front group always includes the Lead locomotive, and all Remote locomotives in the front group follow the commands made by the driver using the Lead locomotive controls. Which Remote locomotives are in the front or back groups are selectable by the driver in real time. One DP train cannot affect another DP train or another individual DP-equipped locomotive not in a train; and an individual DP-equipped locomotive not in a train cannot affect any DP train or other individual DP locomotive regardless of proximity.

Distributed power was originally able to be provided at only one intermediate location within a train. These forerunner systems (Locotrol 102-105 and Locotrol II) required a radio-relay car to be attached via standard multiple-unit jumper cabling to the remote locomotive(s) to provide the radio-control commands and facilitate feedback signals. Later, Locotrol II evolved into the 'Universal' system in which the radio-control equipment was installed on the locomotives themselves, rendering the relay car (variously referred-to as an 'RCU' for remote control unit or 'LRC' for locomotive remote control) redundant.

Locotrol III was the next development-being compatible with both the Knorr-Bremse / New York Air Brake CCB and Wabtec's EPIC electronic locomotive brake equipment, and permitting multiple Remote unit locations as described above. The latest incarnation of this equipment is Locotrol Electronic Brake (LEB), which integrates the GE Locotrol technology with K-B/NYAB's CCBII brake .

Distributed power is used in the United States and Canada, China, and Australia (Queensland, the Pilbara region of Western Australia, and in the southwest of Western Australia), Brazil, Germany, and South Africa.[3] It is also (or has been) in regular unit-train operation in India, Mauritania, and Mexico, and almost made it into operation in both pre- and post-revolutionary Iran. In the south of Western Australia Locotrol is used in the 'top-and-tail' configuration rather than specifically for long-train operation. With the recent advent of electronically controlled pneumatic brakes (ECP)-either hard-wired or radio-controlled-and integrated electronics for locomotive control and driver's cab display systems, DP can now be provided via the ECP brake communication media, and other manufacturers are able to provide this capability. A recent DP system from Wabtec, called PowerLink (which can be either wired or wireless) is in use in Queensland on narrow-gauge coal trains and in the south of Western Australia on standard-gauge iron ore trains.

Other similar operations 'Top and tail' is a phrase used to describe an operation where there is a locomotive at each end of the train; usually to make it easier to change direction at a terminal location where it is not possible to run the motive power 'around' the train (i.e. swap the locomotives from one end of the train to the other); this arrangement is not used specifically to operate longer or heavier trains.

The description should not be confused with 'push-pull', which refers specifically to a train configuration in which the motive power is located at one end of the train only. In this latter configuration, the train is able to be operated from the 'non-powered' end by use of a driver's control position (the 'cab-car') located at that end of the train. Push-pull operation is usually associated with suburban commuter passenger trains.

'Top-and-Tail' is not, strictly speaking, a Distributed Power operation although such a configuration could, conceivably, be used as such. The remote control of a Top-and-Tail configuration is mentioned above (Western Australia) in which Locotrol technology is utilized to provide a solution although not in the context of increasing the train size. The term 'Distributed Power' has been specifically coined to convey the generic concept of removing some of the motive power of a train from its head-end and distributing it within or throughout the length of the train to reduce coupler forces (and, when competently operated; in-train dynamics) and permit the operation of longer, heavier trains. Use of this term ensures that the brand-name 'Locotrol', which is the property of one company, is not itself used generically to refer to the technology of distributed power.




-----Original Message-----
From: nw-mailing-list-bounces at nwhs.org [mailto:nw-mailing-list-bounces at nwhs.org] On Behalf Of NW Mailing List
Sent: Monday, January 17, 2011 3:44 PM
To: NW Mailing List
Subject: Re: DPU trains (was Re: Thunder on Blue Ridge)

Referring to DPU remote control units. Not manned pushers.

Nathan

Nathan Simmons
trainman51 at gmail.com
http://www.t-51.org
KI4MSK


On 1/17/2011 14:52, NW Mailing List wrote:

> Are you all referring to DPU's as remote control or controlled by a  

> crew in the locomotive.

> The old WV law on the H-town District did not permit remote control 

> units in their state.

> Terry Marshall

> H-town, MD

> In a message dated 1/17/2011 2:14:33 P.M. Eastern Standard Time, 

> nw-mailing-list at nwhs.org writes:

>

>

>     > About 6:30 AM stack train 202 went east through Jonesborough TN

>     today

>     > with a DPU pushing on the rear.

>

>     202 and 23G both just came through Christiansburg within the last

>     hour.

>     202 did not have DPU, but 23G did.

>

>     As for DPUs being illegal in WV, NS has been running DPU coal

>     trains out

>     on the Pocahontas Division for the last couple years, so I guess not.

>

>     Joe Shaw

>     Christiansburg, VA

>     http://www.krunk.org/

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