Several related thoughts- Going back to Strasburg and the 8618 pretty much replacing 9331, I remember reading here on RyPN that there was also an 'historic fabric' issue, which factored into not going with a more modern engine. Pricey or not, if anyone in the tourist rail industry could afford the 'drop-in' repower kit, it would most likely be Strasburg. I also wasn't aware that such a kit existed until today.

No idea what this would cost but think about this alternative: a skid mounted genset, consisting of radiator and fan, engine and an alternator (with built in rectifiers), designed to match the generator curve and output voltage that the 44T generator has. Simple, with no gearbox, and I imagine it would be shorter than the engine and gearbox combination, length being important in a centercab.

Its been some time since I've looked at a 44T, but there are auxilliaries under the cab. Lets make them electric. Some of the three phase AC can be rectified for battery charging, as well as for some sort of 'Type E' generator excitation. Three phase AC can also run inverter duty motors, coupled to the air compressors, perhaps rotary screw. (Wires, conduit, motor starters and pressure switches are easier than belts and pulleys; think about FTs and F-3s).

None of this is really all that new an idea. The New Haven had some GE switchers, with Ingersoll-Rand and Cooper-Bessemer engines, interchangable, set up the same way, albeit all DC. This was back in the '30s.

While AC traction motors would be nice, the cost of the controls and inverters would really blow this idea out of the water. Somehow, blowers (again electric) have to be added to the 733s, and I was told years ago that they don't like power braking. A pressure switch on the independent, cutting out generator fields or dropping out the power contactors, should be a big help there.

EDM
Raving Rock, NJ

Thank you - a thoughtful and concise response. Now, where do we find those gensets with built in rectifiers, power to spare for the auxiliaries, and a workable power curve?

I'm not going to consider the "original fabric" thing since we're talking about rolling stock in the collection dedicated being used and altered as necessary to stay useful. Once the decision has been made to use it rather than conserve it, that ship has sailed. Conservation of the old motors and generators can certainly be done to make a very interesting technology display.

dave

Okay so with all of that work, you've now probaby exceeded the cost of casting new heads. Is there not some way of making these newer cast (sorry, I mean hypothetical) heads stronger than the ones of yore? There has to be some way in the computer age to design something that can withstand years of abuse. A head is not exactly the most difficult piece of machinery on the face of a planet. It would sure beat putting a brand new truck engine in.

Cummins Engines manufactures the genset units currently in use, skid-mounted and ready to wire up to locomotive traction systems. Since these genset are often used to repower first-generation diesels, which provide the chassis, it is not inconceivable that a Cummins genset or two could be mated to your 44-tonner.

http://cumminspower.com/en/products/generators/

Mike

Among recently produced engines that are still readily available on the market and will still be supportable by the parts networks for a considerable time, the Caterpillar 3408 might also be a viable alternative, allowing you to replace just one of the D17000 engines in a 44 tonner. It is a very slightly smaller engine (5.4 x 6.0 bore and stroke vs. 5.75 x 8 in the D17000) that produces more power than the pair of D17000 engines.

Suitable transmission options might include the 480VAC 400 kW alternator used in a CAT SR4 genset rectified to DC by EMD AR-10 diode banks, or driving a GE 752 or EMD D79 oil drilling rig generator if you prefer all DC (but weight and space could be a problem).

Leave the D17000 under the other hood as a museum display and ballast.

I offer this only as a suggestion for the interesting question raised about repowering one of these locomotives. You may see other solutions, there are many engine and equipment combinations that could be viable.

PC

This is a topic that has tremendous relevance at the Southeastern Railway Museum. We have two rather tired 44 tonners. Since we only pull two cabooses on most days, we like the little center cabs. Recently we've had to sacrifice the "ease on track structure" and fuel economy for the reliability of larger EMD locomotives. The "younger" of our two 44 tonners is in the shop for an overhaul that *should* put it in good repair for a while...but the aforementioned issues will likely prohibit it from being the long term answer.

I've been looking into various options, paying close attention to the rebuilds that the military did (through various contractors) in the 1980's. The DOD solved the main generator RPM issue by using the GE 5GT (I think) main generator that was used on the 110 ton center cab GE's, which spun at a higher RPM. My research shows that this was fairly standard operating procedure on the 44, 45, 65, and 80 ton engines that the military rebuilt. One would assume that they figured, as I do, that a reduction gearbox would be just another piece to eventually break. Of course we'd like to find a way to keep rebuilding the D17000's to maintain historic fabric, but we have to perform a balancing act to fulfill our stated mission, which is to maintain an "operating museum". We've looked into acquiring one of the DOD locomotives, but they seem to be fairly popular, for obvious reasons. LTEX seems to be getting all of the rebuilt center cabs that they can get their hands on.

Andrew Durden
Operations Manager
Southeastern Railway Museum
http://www.srmduluth.org

Well, no.....it really wouldn't - you see then you'd have this really cool, beautiful nkice new hypothetical head sitting on a worn out hunk of junk block for which there are also no parts. So, you throw a rod through the block and then........
boat anchor woth a shiny new head.

dave

I stand by my earlier comments about having resources to tackle the problem of the D17000 engine.

One of these could be the basis for a 44 tonner repower:
http://youngstown.craigslist.org/bfs/3356576327.html

Just need a rectifier and a really good crew of tinkerers to make everything work.

Go to the website listed below. The A.P.U. unit can be dropped right in a center cab with the I.G.B.T. rectifier set up.It is a simple air cooled unit, The only thing I don't like (for a stand alone system) is the engine is not variable speed. It pretty much runs wide open and the throttle points govern speed. This is handy for building air quick.
I have never been impressed with the air compressors on the G.E.'s even in good shape using this set up with a regular shop air compressor would equal the output of the factory set up.
The air cooled choppers system is fairly affordable. You could use any generator with enough K.V.A.
The problem with the Cummin's set up is you have to use capacitors to get the electrical power needed. (the same as the above mentioned system). If you want to get away from this the only real way I am aware of is to have some make the Alternator the size you need and rectify it.
I have not priced a new D.C. Generator so I can't comment on that option.
www.leanandgreenlocomotive.com

I'm talking about the historical integrity of these locomotives. While we're at it, why not just send it out for the ECO conversion? Is the D17000 the worlds most unrebuildable engine? I believe that it's just it falls into the case that steam locomotives did. There are no more commercially avaiable parts and if you want to continue to see them run as built, it'll have to be fabricated. It can be done or else every operating steam locomotive would be cold and dead. The question is, why doesn't anybody want to? D17000 engines were used in other applications right? What are those people doing to keep their engines running? Caterpillar has a cult following. Why not look to them for answers?

From experiences that my family has had (it's been years since we've had a D17000 powered piece of equipment at my home), the D17000 is generally a durable asset. Case in point are the two D7s that my grandfather, Edward Walenty, has on his property. Both operate in my younger brother would describe as decent (this is a young man who has got a D4 running after roughly two months of work spread out over the summer two years ago), with the main impediment being the cosmetic condition. We had a D7(its been almost 15 years since the machine left my home, so I might be incorrect on the model) that was used for major yard work when I was a toddler. It went to my grandfather, but with a flurry of equipment trades and aquisitions (including the aformentioned D4) over the last five years, I've had trouble keeping track of what's there and what has found new homes.

[quote="ns2110I'm talking about the historical integrity of these locomotives. While we're at it, why not just send it out for the ECO conversion?[/quote]

Because once a piece of equipment is designated as part of the use it up collection absolute historical integrity takes a secondary role relative to its being used, and used up eventually, for interpretive purposes. If you use it you destroy its historic fabric bit by bit until you reach critical mass. If you wish to preserve its historic fabric you don't use it. On very rare occasions.....like the John Bull......you use it just a little and document it in use so that you can show what it was like in use without using it up too much in the process.

I'd be very happy to resuscitate a couple dead critters I'm aware of right now with ECO kits, which would make for a sutainable and clean means of still using appropriate shortline style equipment for a specific interpretive need.....if the group involved could afford the conversion. Pretty soon they won't be able to afford to not convert in some way. The only things missing are dollars, will, a plan, and the ability to face a situation realistically and deal with the consequences without getting emotional about it.

dave

Jack makes some very interesting points......

How do you install a new power plant based on a system designed to provide a constant RPM (for 60 hertz AC) and output of power with a control system designed to vary the RPM and voltage of DC (0 hertz) power?

My guess is that controlling the voltage using some chopper or VFD setup before rectification and letting the AC genset do its thing is maybe the easiest based on available off the shelf stuff.........but not the most elegant or like the original way of using the control system left in place.

You could use a trolley type controller that transitions the motors and cuts resistors in and out..........still left with the roaring genset even sitting still.

Maybe we HAVE to go to a DC generator to get those characteristics?

dave

You can adapt a 480VAC commercial power generating alternator to do the job, rectifying the output to DC, but you usually have to use a throttle schedule selected to make up for the output of these machines being limited at low engine speeds, and to provide adequate air flow in the lower notches if they use a fan on the rotor. For example, instead of notch 1-8 being individual speed changes, you may end up with solutions like notches 1-4 being at notch 4 engine speed while the excitation system defines the power output, then 5-8 being engine speed changes as well as excitation controlled power increments.

PC

If the D17000's were so bad, the heads in particular, how did they last so long in service? Were owners constantly replacing heads? Even if so, doesn't their longevity imply that the head replacement needs weren't that unbearable?

Of course, that was when they were available but it sure sounds like someone could go into limited production on these and spread across the entire user base (not just rail) the costs could be brought down. And that's just with the OEM design, as it sounds like altering the critical area is not possible without other changes that make it untenable. I don't suppose some alloy rather than cast iron would work.

Steve