In their Nov/Dec issue Diesel Era magazine started a series on EMD’s GP9. This first issue covered ATSF and B&O. In the discussion of Santa Fe’s GP9s rebuilt between 1978 and 1980 and redesignated as GP9us it states that, in addition to the installation of the angular cab
I can understand why railroads would deturbo units . . . . . they are expensive to maintain and if you no longer need the punch of the turbocharcher why continue to pay for it? . . . . . but what is the incentive for railroads removing dynamic braking?
I don’t know nuttin about those particular locomotives, however …Dynamic brakes were useful where the locomotive ran trains on significant downgrades. If a locomotive was reassigned to duties different from this, such as a yard switcher, unnecessary equipment would often be removed such as turbochargers and dynamic brakes.
All well and good! . . . . . but it does raise this point:
turbochargers and dynamic brakes are frequently removed because they no longer become necessary for a specific locomotive’s operation. Turbochargers cannot simply be “turned on and off” so-to-speak so they are going to have to be removed to eliminate the possibility of an expensive breakdown; dynamic brakes, on the other hand, are selectively controlled from the cab and can be turned on and off. Railroads don’t just do things because they wanna-do’em . . . . . they do things because it will render some future benefit of either efficiency or black ink . . . . . so, if a railroad elects to de-dynamic brake a unit it follows that the railroad must deem that the short-term expense of removal will generate black ink on the bottom-line. Which raises this question: is there any expense in dynamic brake operation other than the expense of maintenance? In the case of the regenerative braking on electric locomotives electricity was put back into the grid saving money. I guess what I am asking is if it costs money to operate dynamic brakes.
I guess that what I am trying to ascertain in this post is, if I relegate my geeps to yard or industrial switching service does it follow that I would want to remove the dynamic brakes not just because, in their new operating environment, they would seldom, if ever, be utilized but because removal would increase the efficiency of the locomotive in some way?
Most of these ‘re-builds’ were for local service. The D/B equipment was removed, which made for a ‘liberated’ 4 stack exhaust. There really was no need for D/B in local service, and many times it was the old series loop type that sufferered from the bad connections between units.
I don’t believe that it would increase the efficiency of the locomotive, but it would increase the number of spares that the RR has on-hand. I’m sure that the dynamics on some of the older locomotives would/could interchange with other units that are newer and therefore would still serve a purpose as a spare, and would of course save the RR money by not having to buy a new or refurbished unit. So by removing the DB’s from a unit that will no longer require their usage and allowing those parts to be kept as spares for the units that will in fact need them, saves the RR money in the long run.
I’m also sure that the same could be said of the turbo on units that have been de-turboed, the turbocharger unit and its associated parts could be kept as a spare to use on a unit that would still need the parts.
Federal law requires that railroads maintain the systems on a locomotive in operable condition. If there are dynamic brakes on a locomotive, they must be maintained and in operable condition. So regardless of whether the railroad uses them, it they are on the locomotive they have to be tested and maintained. Same thing happened with class lights. the railroads stopped using them but Federal law required them to be maintained on the locomotive if it was equipped with them. So, just like the dynamic brakes, the railroads pulled the class lights out and welded sheet metal over the openings.
For dynamic brakes you also have the potential for openings in the car bodies where water, snow, dirt and rust could collect, the plating over the openings reduces the chances of rust and is cheaper to paint.
No operating efficiency only maintenance efficiency.
I wish to thank every one who took the time to respond to this posting and for the wealth of information garnished from those responses. You fellows are the greatest.
One of the things I had not thought of was that federal regulations might require their maintenance in operable condition if so equipped. I know that was true with the steam generating equipment on passenger diesels; the steam generators had to be removed before the units could enter freight service if that was the railroads intent. In fact it was Santa Fe who, when they removed the steam generating equipment from their acquired Amtrak’s derailment prone SDP40Fs, that the derailment problem had been caused by the boiler water sloshing around in the tank above the rear truck setting up dangerous yawing in the units when either entering or departing curves. When Santa Fe removed the boilers from their acquired units they reported that the tendence of the units to yaw on curves dropped to almost zero. This federal mandate was also why Santa Fe pulled their FP45s out of the passenger pool prior to the beginning of Amtrak; because it was no longer being used the steam generating equipment was removed eliminating the possibility of Amtrak getting its mitts on them.
The only legitimate reason would be for simplified maintenance. If a locomotive has a feature, (grids, Boiler, extra lights etc) by law they must be maintaned in working order. In addition the grids and wiring are another great place for a system to ground itself and render the locomotive a big, rolling anchor.
I’ve always found it ironic that after AT&SF disabled the DB on the early geeps they became common power for use on locals and through freights in Southern California, I have photos of a set leading the Southwest Chief over Cajon Pass in 1982, normally a GP30 was assigned to this helper pool, must have been elsewhere that day!
Wait a minute on the legitimate reasons. IC bought some retired BN SD40’s and has no grades or hills of any consequence on its lines. With dynamic brakes it is possible to have too much braking. As I recall their maximum was 12 axles of DB and no more. Any engines beyond that required the engineer to throw a switch in the cab of the additional units locking them out from control by the lead unit. I would think that plating them over helps prevent water and air infiltration into the carbody.
SImple maintence story for ya. After the PC merger, Pennsy SD7s from Madison IN were in an NYC shop for repair. The dialogue went something to the effect of:
“Hey John? What’s this?”
“I Dunno, what’s it say on it?”
“Uh, Dienam-ick… Braking. Do we need it?”
“Not sure, let’s take it off just to be safe, so it doesn’t break.”
“’ 'Kay”
Same guy who told me this story, who worked on the Madison Hill, also told it it’s just a &^%%^%% flippin’ barrel of monkeys trying to safely get down a 6% incline without a dynamic brake, especially one thats supposed to be there. They got those things put back on REAL quick.
There was a story on this a while back in Trains or Classic Trains - I don;'t think anyoen realized it until they started down the hill. Then it was almost too late.
The Rock Island, I do not believe, ever purchased any new power with dynamic brakes. It did purchase some used F9 units from the UP and subsequently removed the dymamic brakes. It also purchased some used GP 7 units from the Rio Grande with dynamic brakes, however they could not be used with RI units due to different brake system and I can,t find any mention of the dynamic brakes being removed on the Rio Grande units. It seems the Rock Island had no use at all for dynamic brakes.
Selected Railroad Reading: Is this Train in emergency? Trains, April 2001 page 58
Runaway, kind of, on Madison Hill
( “CLARK, WARNER J.”, INDIANA, PC, REMINISCENCE, TRN )
It may also be that in order to use the dynamic brakes, the main engine and generator need to be running at something more than ‘Idle’ speed so as to provide a ‘field’ to the traction motors for them to generate the dynamic braking current. I’m saying that based on my inference and speculation from 1) my observations of a NS pusher on a descending train going around Horseshoe Curve last August - it seemed to be in about Run 6; 2) other posts on other threads about that and other dynamic brake operations; and 3) NS Special Instructions in the ETT for the Pittsburgh Division that limit the dynamic braking ther
Also agree about the need for the main alternator to provide a field current for the traction motor - with no field there is no generation of electrical power to be dissipated in the dynamic brake grids - thus no braking. I’ve been to Horsehoe myself and the trains going down are just as loud as the ones trying to grind up the hill. Someone once said the increased setting was due to needing to keep the coolign fan runnign over the db resistor grid - but with anything modern where the cooling fans are electrically driven that doesn;t make much sense. With a mechanically driven fan I can see having to speed up the diesel to blow more air over the grids. The field current is much more logical though - the stronger the field, the more braking action there will be, up to the point where the field is SO strong it overcomes the limit of adhesion and the wheels just start to slide.
The SD40-2s and SD50s would have the traction motor blower mechanically run off the engine. I think part of the revving up is to keep the motors cool. The engine revs up, but the fuel rack setting is about where it would be at notch 2 or 3. Not much load in dynamic. The electric fans on top should be able to tap off the current generated in braking.
Newer SD40-2s won’t rev up until you are pretty deep into dynamics, usually 6 or so. I would think SD50s would be the same way, unless modified by NS to rev up for better cooling.
I would imagine the NS restriction is to leave a bit of a safety margin, only going up to 6 on dynamics.
