Fast loading with a contemporary diesel sounds like a job for a hybrid. Having full power available for even just 5 min from the charge pack at start should be enough, what with extended range dynamics for charging on the other end.
The issue of optimizing loading vs. minimizing transient smoke in a four-stroke-cycle locomotive engine has been around since the first Alco-GE road freight and road passenger units of the mid 1940's.
The NHRR tried a scheme such as Don described in the late '40's on their FA's. This was deemed a failure over the course of one day.. Over time, there were mods made available on the Alco 244 engined locos for the engine governor, turbocharger (replacement of constant pressure design with pulse), fuel injection, etc.
On the Century Series, Alco employed a mechanical dashpot attached to the fuel injection linkage biased against intake manifold pressure for the 16-251C...which apparently did not find much favor with the end-user.
Some U-series were built with a modified engine speed schedule, reducing the number of engine speeds for eight to three in conjunction with the standard eight notch throttle.
CPM500
In the 1970s SP moved its 10 SDP45s from the freight pool and Amtrak lease to the San Francisco Commute Pool. In the factory configuration, they were unable to keep the schedules that had been routine for the FM trainmasters they were to replace. Bayshore did some minor changes to generator excitation and boosted traction motor blowers to give them more "kick" which made them very successful until Caltrain got its own motive power.
In mixed FP7/SDP45 lashups in Amtrak service the FP7s loaded first, but the SDP45s caught up pretty fast. An 11 car train was moving about 30MPH by the end of the platform. I saw similar behavior with an FL9/P32AC-DM lashup on an Amtrak special movement in the 1990s.
Without major changes? No.
The loading rate on GE Dash 7s and 8s is based on avoiding smoke due to turbo lag. Reducing turbo lag would take some doing - you'd have spool the turbo up faster by some means - reducing the exhaust manifold volume or blowing compressed air on the turbine blades might help. Or provide intake manifold boost from by some other means.
It's 80 seconds from idle to full load on a Dash 7 with CHEC excitation. Worse is that half the HP comes on in the last 20 seconds.
I have heard that some power plants that use similar Alco 251 engines for back-up generators can get from cold to full HP in a very EMD-like 25 seconds by utilizing the compressed air blowing on the turbine blade trick.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
Speaking of ALCO's, they would load up right now.
But, the all time best may have been the FM Trainmasters. Now there is one diesel I would have liked to have run. I have been told that you could stand at the front of the engine and couldn't catch up on the rear when the engineer wound it up (Folks, there are some caveats to doing this, so, DO NOT TRY THIS AT HOME!!! ) It was getting very late in their lifetime, a few were still around, they just never ran them on my district.
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If the Alco PA's were "honorary steam locomotives" then the 6 axle GEs I saw on Mexico's west coast in the 70's and 80's were "honorary" Alcos; loading fast, they smoked...
There' a VCR tape, Pentrex maybe, that spends a while on Super 7 up-grades done with US kits, a lot more than the 15 or so, WP U23B's done in the US., I think some went to, or were manufactured in South America...the up-grade kits.
SP's DL series Alco were in the early 60's detuned to load up at a rate which diminished/reduced smoking. Heil Ringelman (gray scale cards held up to smoke to assist judging the smoke's density.)
So that twerking, oops, tweeking any loading scheme to increase loading speed or diminish exhaust smoke can be easily and readily comprehended....e.g the last couple of msgs.
CPM500 The simple answer to your question is 'yes'-but the end-user could not accomplish this. A job for GE. Loading rate on a Dash-7 is controlled by the CHEC panel. So, one or more components on the CHEC panel would have to be modified. There is no information available to the public on board level design and operation of the various cards that make up the CHEC panel. Loading rate on a Dash-8 is controlled by the 'EXC' panel, which is microprocessor based. The operation of the micro is governed by software-which is closely held by GE. End-users do not have access to software-other than to load it onto the loco. This is only a partial answer to your question-without giving consideration to systems like the governor/EFI or the turbo speed sensor. CPM500 I can make the GE dash 7 locomotive do almost anything I want them to. From the settings inside the CHEC panel to adjusting engine RPMs. Dash 8 engines are a little harder but they can be tweaked a bit at the governor. Writing it all down would be areal chore though.. Randy Stahl
The simple answer to your question is 'yes'-but the end-user could not accomplish this. A job for GE.
Loading rate on a Dash-7 is controlled by the CHEC panel. So, one or more components on the CHEC panel would have to be modified. There is no information available to the public on board level design and operation of the various cards that make up the CHEC panel.
Loading rate on a Dash-8 is controlled by the 'EXC' panel, which is microprocessor based. The operation of the micro is governed by software-which is closely held by GE. End-users do not have access to software-other than to load it onto the loco.
This is only a partial answer to your question-without giving consideration to systems like the governor/EFI or the turbo speed sensor.
I can make the GE dash 7 locomotive do almost anything I want them to. From the settings inside the CHEC panel to adjusting engine RPMs. Dash 8 engines are a little harder but they can be tweaked a bit at the governor. Writing it all down would be areal chore though..
Randy Stahl
On the other hand, the few GE AC units that I was able to operate did seem to load up faster. I never got a chance to run one on a regular basis in order to truly determine if this was the case. However, I do think that GE's AC units had the potential of being the best performing unit they ever made.
Anything is possible, But...
GE locomotives like the Dash 7/8/9 line use the FDL power plant.GE limits the 'loading up' as the turbo does not spin up as fast and there will be lots of black smoke(unburned fuel) EMD turbo units get around this as the turbo is connected to the diesel by a centripical cluch up to about RUN 4, then is free wheeling off of the exhaust gases like a normal turbocharger. In this day of EPA exhaust limitations, no one is going to 'tinker' with the loading.
To expand a little further, early GE U-Boats and the follow on Dash 7 line have not been popular 'rebuild' material. GE did offer a 'Super 7' rebuild option, but I doubt if more that 10-12 units were ever done. The Dash 8 line were the first of the real micro-processor controlled locomotives in the N/A rail industry and sold quite well. The problem is that they have the older power plant as well, and many have been scrapped/traded or sold to Canada(UP & BNSF). Buying new locomotives that meet the EPA regulations seems to be the trend.
EMD has offered a re-power package using a 710ECO re-power package and that has sold quite well. GE has offered a GEVO 'Straight 6' re-power package, but I am unaware of any conversion by GE or a railroad at this time.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
CPM500 Way too general a question. Be more specific as to mfr., model, etc.
Way too general a question. Be more specific as to mfr., model, etc.
Figured he identified the manufacturer and models in the title of the thread.
Never too old to have a happy childhood!
Is it possible to change the excitation causing the loco to load-up faster w/o major changes to the electrical system or motor
Thanks SouthernAlco
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