Why no GEVO-8? There's an 8L250, after all.

[mtuandrew]

We're familiar with the GEVO-12 from the ES44 series, the GEVO-16 from the Chinese ES59s and CSX's ES60 conversions, and the GEVO-6 that GE is shopping around as an ES23 conversion. Why no GEVO-8?

Seems to me that a GEVO-8 would hit a sweet spot for repowers. It's EPA Tier 4i-certified and good for easily 2,700 horsepower - a bit lower than legacy GEs and EMDs, but not bad at all if you're looking for local power. Only problem would be that they're a few feet longer than the 16-FDL and presumably the 16-645, but presumably you could design a package that would fit such an engine.

Of course, an 8V250 would be a better start, but there's only so much we could ask for.

[MEC407]

I've been wondering the same thing for years. I think a V8 GEVO would be a much more compelling repower option than an L6 GEVO, and I'm not certain that an L8 GEVO would even fit in most of the locos that are ripe for repowering. I realize there are balance/vibration issues with V8s generally, but that doesn't seem like it would be insurmountable. GE made it work with the V8 FDL.

You'd actually be looking at around 3,000 HP for an 8-cyl GEVO (4400 ÷ 12 = 366.6. 366.6 * 8 = 2932.8, and it can go higher because they're rating the 12 at 4600 HP in the MPI HSP46, so a V8 rated similarly would be 3066 HP). That's very much the sweet spot when it comes to repowering older six-axle locomotives. EMD knows this well and has been very successful with the 12-710.

[mtuandrew]

Exactly, MEC407. A GEVO straight 8 might only fit in SD45s without major surgery, but it definitely is in the right hp ballpark to repower the bulk of 1970s and 1980s power. This month's issue of Trains Magazine cites the GEVO Series as being the most populous series of locomotives on every Class 1, so the mechanical expertise is certainly there. And, if GE chose to make an 8V250/GEVO V8, it wouldn't be the first time they created a V8-powered locomotive. Erie certainly has the experience to split their GEVO-16 in half width-wise and take care of any resultant balance problems, rather than length-wise as they do today.

[v8interceptor]

General Electric has specifically offered both the inline 6 and inline 8 250 series engines (inline GEVO) as locomotive re-powering options and I'm sure they've done their math about fitting them into existing locomotive frames:


http://www.rrpicturearchives.net/showPi ... id=1324365


http://www.fasterfreightcleanerair.com/ ... Lawson.pdf

Obviously, The 8 cylinder engine is longer than the 6 cylinder but it is meant to be installed on longer six axle locomotive frames. I would imagine that the 8-L250 package is aimed at older 6 axle Dash 8 units and I doubt there would be any problem with accommodating the new engines on frames that long.

GE also has the option of offering the P616 Powerhaul engine for these applications; the 16 cylinder engine is rated at about 3,700 BHP (3,490 HP for traction) in current locomotive installations and will be offered with an EGR based Tier iv compliant emissions control system in the near future.
http://www.ecomagination.com/portfolio/powerhaul-engine

[MEC407]

Yes, they offered them, but not a single one has been sold to any railroad in North America. I can't help but wonder if the inline configuration has something to do with that.

[MEC407]

Another possible factor is that the FDL is a very economical engine and it might just make more financial sense to do an in-kind rebuild, as NS is doing, than a complete GEVO repower which would obviously be more costly from the standpoint of the engine price itself as well as the engineering required to shoehorn an L8 into the space previously occupied by a V12 or V16. (I do believe the L8 GEVO is longer than the FDL-16; exactly how much longer, I'm not sure.)

[NorthWest]

I think a lot has to do with the amount of locomotives remaining. EMD has done a lot of 710 'repowers' because a large segment of their Dash-2 production survives. Most of the GE Dash-7s have been scrapped, so there are fewer cores for possible conversion. The Dash-8s aren't old enough for a full repowering.

[Allen Hazen]

At the size of locomotive diesels, V-8 engines seem to be difficult. (See: Alco C415 issues. See: EMD's change from 567C to 567CR partway through SW-900 production.) The FDL-8 seems to have been an exception: the U18B and lots and lots of GE export locomotives used it successfully. But the GEVO is a different design. (Something that may be relevant: the FDL has an unusual configuration in which only the pistons on one side have rods connected to the crankshaft, the pistons on the other side having short rods that connect to the middle of the "master" rod on the other side. This MAY -- I don't know, I'm not a mechanical engineer -- be relevant to the dynamics of the engine in ways that make it less prone to problems than other large V-8. The GEVO does not have this feature: it is a conventional V-engine, with pistons on both sides rod-connected to the crankshaft. This MIGHT be relevant.) Designing and de-bugging a V-8 version of the GEVO engine would be a major project, and it may be that GE hasn't wanted to invest in it. My guess is that for the past few years all their diesel-engine engineering efforts have been devoted to making the Tier-4 V-12, which is a significantly different engine from earlier versions of the GEVO.

[v8interceptor]

The Dash-8s aren't old enough for a full repowering.

Why not? Several railroads have recently been rebuilding/repowering -50 and -60 series EMD's with the ECO engine package and these units were built around the same time as the Dash 8's.
Of Course there really aren't that many 4 axle Dash 8's compared to the number of contemporaneous EMD's...

[NorthWest]

Actually, I forgot how old they are. Time moves fast.
They are about 30 years old, which is about time for their fourth heavy maintenance. This has been traditionally about the age when GEs die, and many Dash-8s have been scrapped. NS believes that they are worth rebuilding, but they notably are still using the FDL in their rebuilds.

[MEC407]

CN also sees the value in older FDL power, having recently purchased numerous Dash 8s from UP and BNSF. CN has apparently been doing in-kind rebuilds of theirs as well. The old idea that GEs aren't rebuildable simply isn't true anymore.

[MEC407]

many Dash-8s have been scrapped

I'm less certain about this. Almost every Dash 8-40C, Dash 8-40CW, or Dash 8-40BW ever built is still in service. The early ones — the "classics" — which were more like a Dash 7.5 — have mostly been scrapped, but the true Dash 8s are mostly alive and well.

[NorthWest]

"Some" would have been a better word. Almost all of the C-C units survive. Many of the B-B units have been retired, with UP having retired almost half of theirs. A large proportion have been scrapped. Others have been derated. They don't have as much of a purpose anymore. Most of the units that CN picked up were actually lease returns that CN picked up from the lessors after UP and BNSF decided they no longer wanted them.

The Dash-8 step up in quality is what is keeping them around, as is the power shortage and Tier IV worries. To be honest, I hope they stick around for as long as possible, because I'll miss them. The rebuilds are cleaning up the trouble spots, which is good.

To return to the thread topic, one of the main reasons why GEs in the past have not been rebuildable like EMDs is the FDL itself. The crankcase in older locomotives tends to crack, and so most rebuilds have had new prime movers. I suspect NS is using new FDLs in their rebuilds, but cannot confirm this. It is probably easier to do this than put in GEVO repowers.