I'm working on plans to bring the Armco B-71 back home from Minnesota. Our intention is to restore the B-71 to operating condition for use as an operating demonstration piece. Since sister engine B-73 is operable and in original condition I am not all that concerned with maintaining the B-71's historic integrity, I am much more interested in B-71 becoming a reliable runner.

The locomotive is in suprisingly good shape, but the Hamilton diesel engine is unsupportable and has to go. But what are my options for repowering? My requirements are few. First, a new engine must put out 250 to 300 HP at 800-1000 RPM. Second, it must be something supportable with parts and service. I cannot use a modern diesel locomotive engine due to space constraints. The configuration of the engine compartment of the Visibility Cabs precludes use of a 567 or 645 engine due to their wide girth. Such an engine would be overkill anyways, since we just need enough power to move the locomotive and one or two cars on level track.

I got to thinking about the Cummins NTC 335 engines. Our GE 70 tonner has two. These engines can be rated for 250 to 335 HP at a speed 1800 HP. Clearly too fast, but if coupled up to a marine gear reducer with a 2 to 1 ratio that puts the speed right down to where I need it.

I suppose my question for the Forum is if this approach has ever been tried before to repower an older switcher, and if such an idea is plausible or destined to meet with disaster. Are there any other options that I could consider? I had thought of installing one of the MG sets out of the 70 tonner into the B-71, but the 70T is a 250 volt system and the B-71 is a 600 volt system. Even an 80 tonner with the Cummins LI-600 is a 250 volt system.

I've been involved with a couple similar things, and the reducer will work in conjunction with the higher speed prime mover using the old generator. An alternative is to replace the motor and generator with a pair that is matched to provide the power you need at the design higher speed. Might consider using an AC off the shelf unit and converting to DC as a third option.

Phil Johnson just re-engined a diesel, and may have a spare Cooper Bessemer he can let you have cheap.

dave

There is a cat engine with an output shaft speed of 1100, the D398 series. When I came up with the options for repowering the cooper block only two made sense and the other is the alco 251 that they used, seems like I should get a royality for the uncredited use of my idea....in a perfect world I guess.
The block that came out has several cracks, not to good. They also somehow managed to badly damage the guts of the thing which I don't understand as everything tested out to within new limits prior to the '09 season.

In the interest of accuracy, Phil did not repower the thing. He was involved with a project laid out by outside individuals who know what they are doing. The loop does not posses the knowledge in house to do that sort of work.

Dave, thanks for the info. Good to hear that I'm not too far out in left field with this. I don't think that replacing the generator is necessary and may get me into new wiring issues that I want to avoid. So far my research has turned up that a Caterpillar 3208 engine coupled to a Twin Disc MG-5075 SC gearbox with a 2.53 ratio will give me 830 RPM at 2100 RPM and a 274 HP rating. A ZF 311 gearbox would bump that up to 364 HP max. rating.

As I was researching this I learned that the NTC 335 engines are also becoming hard to find parts for. The Cat engine is still supported and therefore a better choice.

Jason, I checked out the D398. I think that is overkill for this application. Would be great if I was repowering the B71 for freight service, but for demonstration service a smaller engine may be preferable.

I had a conversation maybe a dozen years ago with a gentleman down South who had repowered several GE 70 tonners with truck engines. He would not tell me any specifics (I believe he had an idea for a patent-), but he said that it was very easy and inexpensive to do. I seem to remember the name Cummins being mentioned, as well.

My guess, and it is ONLY a guess, is that he used both the truck engine AND transmission, similar to what Stationary Steam has suggested with a marine gearbox. With a truck transmission, you should be able to select a gear ratio that provides the best output range for the main generator. As with the use of a marine gearbox, some sort of transmission cooler should be provided.

One drawback that I can see, right off the top, is that the generator has to have two main bearings, and not be dependent upon the main bearing in the engine to support one end of the armature. I've often wondered (and never found out-) just how the GE 70 ton main generator is arranged. But if the generator in question has two main bearings, a truck engine, transmission and a custom drive shaft should get you most of the way there.

Strictly my opinion here, (although with 30 years in the trucking industry behind it) as far as simplicity, dependability and cost are concerned I would look for a late NTC or Big Cam Cummins, although my first choice would be a Cat 3406B model. I would stay away from the Cat 3208, or any V-8 diesel for that matter. With all of the later model diesels you have to contend with electronics and computers which can complicate control systems and add to the price, ummm, I'm assuming you don't have emissions regulations to deal with? The 3406 Cat is a very dependable, rugged engine with manual controls (a rod between your foot/hand and the injection pump) parts are readily available, and a rebuilt one can be had for between 7 and 10,000 dollars. They are physically about the same size as the Cummins also...good luck!

Cheers, Dave

I may have to install a bearing to support the engine end of the armature. I have my doubts that the gearbox output shaft is capable of supporting that much weight. Fortunately when the Hamilton was installed a new fabricated base was made to support the generator and engine, and this base can be retrofitted to support whatever outboard bearing that I may need to install.

Hillcrest, I'm not locked into a certain engine make or model at this point. I'll check out the 3406. Thanks for the tip.

The EPA emission regulations for locomotives do not cover locomotives built before 1973 and/or under 1000 HP.

I have been around repowers before, including the ones from down south. My self, I would not use a CAT engine as their parts are just overpriced. CATs also do not like half of an overhaul. A friend recently tried to cut corners on his CAT overhaul and had to take it back 3 times. Problems included dropping valves. Cats do not seem to like reground valves. The best thing to do with their heads, is to completely strip them and use all new parts.

You can use a Cummins 855 with around 335 hp. mated to a GE 558 main generator. This is the same generator used in a 65 ton GE centercab. It will do all you need to do at low speeds.

There is no need to run the generator thru a transmission or a gear box, but you do have to watch that the generator can handle the engine RPMs.

You could also use a Cummins "K" series engine of about 450 hp mated to a GE 603 generator. This is a larger 6 cylinder inline engine and the GE 603 generator is the same generator used in off-road heavy haul trucks.

You can also use an alternator, with AC output, but you will have to rectify the AC over to DC. You may be able to pickup a very good used engine/alternator that has been used for stand by power at a hospital. I have seem these for sale at very reasonable prices and with very low hours. They replace them largely because of age and not hours.

All of these combos have been used by my friend down south with great success.

How about a 4 cylinder 4045 John Deere generator (A/C) with a IGBT chopper.Can be had as a complete running unit cooling system and all. Inexpensive , flexible and you can see one in action here in Ohio. Pull anything you could want and give you 480 volt power when needed.
We are putting a Pair of 6 cylinders in a G.E. currently. not bad on price and reuses allot of the original components. Dollar for dollar the John Deere's are proving to be cost effective. They are also proven to hold up well in the long run. Hook up a G.E. Generator and your good to go.
We use MTU-DD in the larger horsepower units.They don't have anything below the series 60 that's approved for use with a single bearing generator, That's why the John Deere's
You aren't going to find much in the way of slow speed diesels.

An entire MG set changeout is certainly a possibility, but since the electrical end is still intact and in good shape I would like to leave that in place if possible. Why make the project larger than necessary? The Westinghouse electrical equipment is original from 1930 and with some TLC can be made to operate for another 80 years. But its still and option.

I'm afraid I will have to respectfully disagree with ALCOC420. Having owned a longhaul truck with a KTA 525 Cummins in it for 9 years and 785,000 miles I got fairly familiar with it. They are 1155 cubic inch engines (vs. 855 for a NTC or Big Cam or even N-14 Cummins) are physically quite a bit larger and heavier, and are horribly expensive to rebuild...on the other hand they last for what seems like an eternity, have tons of torque, and are relatively quiet in operation. The statement about the 3406 is innacurate in my opinion. The company I manage owns 27 of these with anywhere from 2500 to 30,000 hours on them, some obviously having been rebuilt more than once. The only time we've had problems with them "taking" a rebuild is when we've tried to use non-Caterpillar aftermarket/offshore parts...to use an old phrase, you get what you pay for. All of our equiptment operates in severe service (mining) and one piece that we recently aquired with a company we purchased has 26,000 hours on it and has never had a valve cover off...Maybe that makes me a "Catvocate??" Just for a quick comparison, we rebuilt a 3406 and re-used only the block and crank, and had just under $16,000 in parts. We also rebuilt a K model on a Genset, and had a little over $27,000 in parts for a block and crank-up rebuild, but that included the "front-end" lubrication and reseal update which did add to the cost....


Cheers, Dave

I also have to respectfully disagree with AlcoC420, specifically his thoughts on not needing a gearbox or transmission between the engine and generator. Generators are designed to run at specific speeds, to provide specific outputs. I don't know what model Hamilton engine is currently in B-71, but Stationary Steam is looking for something that runs, max, in the 800 to 1000 RPM range.

Most truck and industrial engines run in the 1800 to 22/2400 RPM range, from what I've seen. This would be way too fast for the Westinghouse generator. If the speed were kept down, to really not much above idle for one of those engines, the horsepower output would be disappointing.

Even that master of repowerings, EMD, had issues with matching their 800 and 835 RPM 567s to generators of other builders. I have read (Trains magazine, decades ago-) that there were some interesting challenges getting a 567 to work with a Westinghouse generator from a BLW locomotive without fireworks. The BLWs ran at 625; an extra 175 RPM or so was just too fast.

The alternator and rectifier solution is interesting, but there are other issues, aside from cost. What are the auxiliary requirements on the locomotive? Is there an exciter on top of the generator? Is the compressor driven off the free end of the generator, along with the fan drive and (maybe?) TM blowers? Using a new alternator with rectifiers may effect the excitation and load regulation. Lets not disturb any more auxiliaries then we have to; replace only what we need to.

OK, I'm pushing my idea, but once past the generator bearing issue, this truck engine AND transmission idea should be the lowest cost way to go. It might be worth taking the time to call some local truck junkyards,...err, make that recyclers.

The 44 tonners that the military had rebuilt in the 80's and early 90's used CAT 3306's. I assume that they changed out the generator with something that could spin faster than the old generators that were coupled to the original D-17000's.

You can disagree with me all you want.

I have worked with Johnson Railway Service/Chattahoochee Locomotive Company for over 20 years and they have been repowering locomotives for a lot longer then that.

I have sold them stripped out Alco S4 switchers that they have repowered. Over the years they have used many engine/generator combinations, but one thing they have never used is a gearbox on an engine to run a generator...... The generator attached to the old Hamilton engine, is designed for a low speed engine and would not mate to a newer high rpm. engine. The problem with this old generator, will also be finding any parts for it. Doubtful you will find a brush holder. What about brushes? Have them special made?

If you want to see pictures, I have them on my computer.

I recently inspected several of their locomotives that came off lease from Carolina Power and Light.

One was an Alco RS1 which had a "K" series 425 hp. Cummins with a GE 603 main generator attached to it. This locomotive had a very limited electrical cabinet and was powering 4 GE 752E8 traction motors and was used to unload unit coal trains.

Another had a Detroit "60" series engine attached to an alternator. This unit has a screw type air compressor and had Cattron Remote Control. It also had a very limited electrical.

Another had a 335 hp Cummins attached to a GE558 main generator, it also had remote control and a screw type air compressor.

They have a customer in Brownsville, Pa. that has a 12V92 Detroit Diesel engine in it. The customer has the 12V92s in their towboats, so they wanted this engine. This same customer just purchased a complete rebuilt locomotive from them and it has a 1,000 hp. Detroit "MTU" series V12 attached to an alternator. This was a ground up rebuild, down to a bare frame.

If all you are going to do, is switch cars at low speeds, then you can get rid of more then half the components in the electrical cabinet. Where regular locomotives have 3 to 6 main power contactors, you only need one for series. Good for 10 to 12 miles per hour.

Auxiliary generators are not needed for all generators. I take care of a GE 80 ton center cab locomotive with 2 Cummins 855 engines and GE 569 main generators. The only aux. generator on the locomotive is one large capacity alternator to charge the batteries and it is mounted to the Cummins just like any alternator would be mounted to a truck engine. The batteries provide the necessary current to excite the main generators. The locomotive uses 4 high output marine 8 volt bateries, for a 32 volt control circuit. Voltage for the headlights goes through resisters.

Johnson is not the only one doing these repowers. GE did them out of Cleveland, Southern Rails, Silcott Railway Service, Duffy and son, just to name a few. There is one old Alco S4 in South Charleston, Ohio that has the diesel engine/gen. set, skid mounted and sticking out of the front of the locomotive. They gutted the radiator compartment and the radiator for the eng/gen set sticks out the front of the locomotive.

As for the military repowers, most of these were 65 ton and 80 ton centercabs. I looked at one of these once that was selling at an auction. Very neat repower. It was converted to roller bearings, had "AAR" control stand with 26 air and it did have the Cat engines.

This locomotive's freight moving days are over. What we will be using it for is to leisurely trundle along at 10 mph maybe pulling a caboose or two for a couple of miles and then back. Probably 20 to 30 hours a week during the busy season, probably not turn a wheel for 4 months out of the year.

Any small diesel engine in the right HP, whether it be a Cat, Cummins or Detroit will probably work just fine, and I'll reduce the speed down to the 800 RPM that I need. I'll match the rated speed of the engine to the rated speed of the generator when I do the gear reduction. I'm not all that concerned about the serviceability of the Westinghouse generator and aux. generator, not much goes wrong with them and I have resources to take care of electrical issues. I have a pile of motor brushes that is two feet high, and access to racks of brush holders, so even if I cannot find an exact match I can make something similar work.

The one detriment to this entire project is the sound. I won't have the soothing sound of a low speed diesel throbbing away, but that's the price one has to pay I suppose. The convenience of running a modern, supportable and more fuel efficient engine more than outweighs the auditory downsides.

Someone mentioned compressors. The B-71 has a pair of undermounted motor driven compressors, and I may bypass them and instead belt drive a two stage compressor from the main engine. No need to wear out those compressors, of which there are probably only six of them still in existence (on B70, B71 and B73). I'm trying to walk a fine line of increasing the reliability of the B71 without making very many alterations that could not be reversed at some point in the future.