MCL1981 wrote:I'm still not seeing how going from 3600 HP to 7200 HP doesn't allow it to accelerate faster. Each one has half as much weight to accelerate from a stop.I don't know where the original no quicker acceleration came from but I'm pretty darn sure 2 MU'ed locomotives will accelerate a train quicker then one...
Railroad Forums
MARC To Purchase Siemens Chargers?
- Discussion related to DC area passenger rail services from Northern Virginia to Baltimore, MD. Includes Light Rail and Baltimore Subway.
Moderators: mtuandrew, therock, Robert Paniagua
The gearing on those units doesn't allow for: "1+ 1 = FASTER ACCEL". Unless you're compensating for an above-and-beyond extreme weight performance penalty like a hypothetical overstuffed monster Penn Line consist.
It's not that generic loco can't accelerate faster MU'd. It's that MARC's specific roster of MP36's aren't geared to provide that capability. They can spend money to re-gear them...at a penalty of lower top speed...or they can buy a make that's a bit more flexible with fewer limitations. They're choosing to buy something a bit more flexible with fewer limitations.
The MP36, and specifically the gearing configuration MARC ordered them in, has limitations that make it an underwhelming performance fit for full-time Penn Line duty. That's all. It's got nothing to do with what a generic any-diesel could do...just what their pre-existing roster of that specific make does do and the cost/benefit of trying to tart them up to squeeze better acceleration vs. buying something else better suited to task. They get a lot more for their money buying Chargers to run vanilla push-pull than they do buying extra MP36's and playing gearing tricks with them to run as dedicated NEC double-drafts.
It's not that generic loco can't accelerate faster MU'd. It's that MARC's specific roster of MP36's aren't geared to provide that capability. They can spend money to re-gear them...at a penalty of lower top speed...or they can buy a make that's a bit more flexible with fewer limitations. They're choosing to buy something a bit more flexible with fewer limitations.
The MP36, and specifically the gearing configuration MARC ordered them in, has limitations that make it an underwhelming performance fit for full-time Penn Line duty. That's all. It's got nothing to do with what a generic any-diesel could do...just what their pre-existing roster of that specific make does do and the cost/benefit of trying to tart them up to squeeze better acceleration vs. buying something else better suited to task. They get a lot more for their money buying Chargers to run vanilla push-pull than they do buying extra MP36's and playing gearing tricks with them to run as dedicated NEC double-drafts.
So are you telling me that 1 MP36 with per say 5 or 7 per doubles is going to accelerate at the same rate as 2?
8th Notch wrote:So are you telling me that 1 MP36 with per say 5 or 7 per doubles is going to accelerate at the same rate as 2?
F-line to Dudley via Park wrote:Unless you're compensating for an above-and-beyond extreme weight performance penalty like a hypothetical overstuffed monster Penn Line consist.↑ ↑ ↑
Otherwise...on the vast majority of schedules MARC runs during its service day, not enough to make any tangible difference on acceleration that'll net any change in schedule. Regardless of whether one's own stopwatch from trackside shows a minute improvement out of a dead stop double-draft vs. non- double-draft; it's too minute to reflect in the timetable. Because they're not built or configured to have an extra performance tier to reach for that way. Other locos are built that way. These are built for a pretty narrow midrange performance, and that range ain't something that'll fare well as an rush hour electrics replacement on the Penn Line. Hence, the purchase of a higher-performance Charger.
Why are we still framing this in terms of "generic loco" when it's MP36PH-3C numbered 10-35 as-configured by MARC...and specifically MP36PH-3C's #10-35 as-configured by MARC...that are the locos with too negligible room for acceleration improvement in a double-draft configuration to institute that as a standard practice? The best they can do as double-draft is not arrive to destination slower because they were tasked with carrying a consist more overweight than a single engine's average performance can accelerate without suffering some schedule drag. A ↑stop-loss ↑ scenario that only comes into play on a very small and variable % of the Penn Line schedule...not an above-and-beyond enhancement to the Penn Line schedule.
MP36. MARC's. MARC's MP36's. MARC is buying not-MP36's because their MP36's can't be made to accelerate zippier and arrive at destination sooner.
Will the Chargers perform any better, either by themselves or as a pair?
As no chargers have been completed, any answer would be beyond speculation, would you agree ?
If Conductors are in charge, why are they promoted to be Engineer???
Retired Triebfahrzeugführer. I am not a moderator.
Retired Triebfahrzeugführer. I am not a moderator.
MCL1981 wrote:Will the Chargers perform any better, either by themselves or as a pair?Paper specs-wise, very much so.
Whether the things will actually perform as intended? Well, head over to the Amtrak forum's Charger thread and watch the socket wrenches fly as gearheads debate the wisdom of picking that unproven Cummins engine. Even if they're winners, I wouldn't expect the Amtrak order to finish anywhere close to on-time given how extra debugging for newfangled tech has become the rule rather than the exception. MARC could be waiting a couple years longer for its first units to arrive.
again Amtrak has not ordered Chargers , other funding agencies did .
If Conductors are in charge, why are they promoted to be Engineer???
Retired Triebfahrzeugführer. I am not a moderator.
Retired Triebfahrzeugführer. I am not a moderator.
DutchRailnut wrote:again Amtrak has not ordered Chargers , other funding agencies did .They are all-Amtrak's specs for an all-Amtrak maintained, all-Amtrak operated, all-Amtrak rostered order that happens to have 150 bona fide Amtrak-owned options on the order. Who owns the title deed on the (currently) 58 to (up to) 107 state-sponsored units is a time-waster means of splitting hairs by folding legal documents into fun origami shapes. They're for Amtrak's use on Amtrak's system. Unless something disastrous happens to short the order, more of them will be owned by Amtrak than not-owned by Amtrak...by wide margin.
While we're talking title deed semantics, how about tallying up every commuter rail agency that does those standard-issue sale/lease-back deals with insurance underwriters who "own" the piece of rolling stock? All sorts of irreverence to be had up and down those rosters arguing about whose piece of equipment it really is, eh?
They are PRII standards and not Amtrak standards.
If Conductors are in charge, why are they promoted to be Engineer???
Retired Triebfahrzeugführer. I am not a moderator.
Retired Triebfahrzeugführer. I am not a moderator.
MARC is only going to run 6 car consists due to the 2010 breakdown in 100+ deg F heat that had folks break out windows and exit the train just to escape the ovens. The recommendation made by the investigation that followed was to cut the consists down from 8 to 6 and run more of them over the day.
This is why rush hour trains are roughly every 15 to 20 minutes, and with the rate of breakdowns they're going full diesel.
This is why rush hour trains are roughly every 15 to 20 minutes, and with the rate of breakdowns they're going full diesel.
STrRedWolf wrote:MARC is only going to run 6 car consists due to the 2010 breakdown in 100+ deg F heat that had folks break out windows and exit the train just to escape the ovens. The recommendation made by the investigation that followed was to cut the consists down from 8 to 6 and run more of them over the day.There are most certainly 7 and maybe even 8 car consists on the Penn Line still to this day. I fail to see what having less cars would do to solve that problem. The incident had nothing at all to do with the number of cars or number of people.
This is why rush hour trains are roughly every 15 to 20 minutes, and with the rate of breakdowns they're going full diesel.
Page 28 of the MARC Train 538 Incident Report: Recommended that HHP engines pull no more than 8 cars, leaving diesels to pull 9+. The schedule review for reducing the length of train sets is noted on page 51.
So yes, I'm wrong that the limit was 6, but no, it was due to the 538 incident.
You do have to remember physics, though. The more weight (cars AND people) to move means more power is needed, and added strain on an engine over time.
So yes, I'm wrong that the limit was 6, but no, it was due to the 538 incident.
You do have to remember physics, though. The more weight (cars AND people) to move means more power is needed, and added strain on an engine over time.
It's reactionary non-sense. That failure was due to the POS HHP having the equivalent of a windows blue screen of death. The number of cars, number of passengers, outside temperature, and phase of the moon had nothing to do with it. So typical clueless managers want to make it look like they've done something about, and change something unrelated. Having more trains with less cars each will just mean the same amount of people in the same amount of cars stuck in a traffic jam not moving anywhere. They're just taking up more track doing it!
MCL1981 wrote:It's reactionary non-sense. That failure was due to the POS HHP having the equivalent of a windows blue screen of death. The number of cars, number of passengers, outside temperature, and phase of the moon had nothing to do with it. So typical clueless managers want to make it look like they've done something about, and change something unrelated. Having more trains with less cars each will just mean the same amount of people in the same amount of cars stuck in a traffic jam not moving anywhere. They're just taking up more track doing it!We can basically agree that the electric engines have been terrible for MARC. But the funny thing about the changes? They actually got more people on the Penn Line.
I wonder what color the schedules will be when it's 100% diesel...