At the suggestion in another thread will start a thread about the minimum motive power needs of various AMTRAK trains.
A. Congress meddled into AMTRAK by requiring a certain on time performance ( 80% ? ) from it and the host RRs. This requirement makes AMTRAK do everything possible to shave minutes off its trains times whenever there are delays.
B. There is a preception by potential passengers that any mode of transportation that can operate on time is doing a good job.
C. Along with "B" is any public awareness that as scheduled times are decreased an increase of passengers all out of proportion to the actual decreases of travel time.
D. On time trains make their turns to an outbound trip more likely.
E. There are several constraints at present that limit the number of locos or motors on various trains.
1. A finite number of both
2 Most units still use DC traction motors. Exceptions are about 29 AEM-7s that were converted to AC traction, The 15 HHP-8s are AC traction with many common components to present ACELA train sets which are all AC. There are a few diesel locos ( 10 ? ) that were bought or converted.
3. DC traction motors seem to have several disadvantages that will probably see their demise.
a. Fine snow gets into traction motors and causes the motor to ground out thereby loosing 700 HP for each grounded motor ( P-42 ) . Have heard of some locos grounding out all their motors in a 25 mile streach.
b. Salt spray although only occasionally can ground out a motor.
c. For what ever reason DC seems to be limited more at design max speed than AC there by slowing acceleration to max speed ( 110 for P-42s & modified P-40s ).
d. Trains on the NEC pulled by AEM-7s DCs cannot maintain schedule whenever they are more than 9 cars with only one electric motor.
IMHO there are several reasons that AMTRAK needs more HP than appears at first
11. AMTRAK stops and starts more than most freight trains ( local freights the exception )
12. Extra HP is needed to accelerate quickly to track speed. Some examples
k. There are many station stops scheduled for any train and a quicker acceleration means there are opportunities to gain 2 - 3 minutes with each station leaving.
l. Many single track lines have sidings too short for present day freights with AMTRAK in those holes. AMTRAK has to accelerate out the other end. ex; eastbound Cardinals on the BBrRR
m. On congested tracks AMTRAK has to go into a siding facing a opposite direction freight. Then AMTRAK has to back out and reverse direction allowing 2 times for quicker acceleration.
13. Many times trains ( especially single engine trains ) cannot make passenger train track speeds on uphill ruling grades due to longer consists. ex; Pennsylvanian up both sides of Horseshoe especially when B-32 is substituted. SWC up Raton, CZ west of Denver. Starlight when it starts taking the new route out of Tacoma southbound, ( at least 2 Sounders have already stalled there)
14. The 110 MPH sections of St Louis & Michigan speeds are not being met with 1 loco and require 2 locos to make that speed. That may be due to DC traction motors ??
15. Operating in snow conditions usually requires extra locos and maybe even extra freight locos. Empire Builder #8 / Mar 20 had 3 P-40s led by 2 BNSF ES44 ACs
16. There is the need for the failure of one loco on a two or more train to be able to continue the train at a reduced speed until the train can go to a location to receive another loco.
solutions
21. AMTRAK may be able to increase its loco availability several percentage points but any major wreck, another problem with the P-42 trucks, or other unknown problem could eliminate any gains ?
22. The announcement that Illinois is now leading the purchase of 35 ( ? ) new locomotives may mitigate the power shortage but that probably will take 2 - 2-1/2 years for deliveries to begin. Once the new locos come on line replaced units can be spread out. It may be that one of the new locos can maintain 110 with the present consists.
23. When the new Atlanta station is built ( 20?? ) the one non needed loco south of Atlanta can enter the loco pool.
24. A final solution will be the purchase of new AC traction motored locos that are rated for 125 MPH. The only problem will be if the higher gear ration actually decreases tractive effort of each AC motor ??
25. Of course there is the cost factor. According to the report on the EAGLE it takes from $175 K - $250 K to add a loco for one year to one train consist. So a big cost to say the EB. However some of that cost can be reduced by less crew overtime.
Blue Streak, you have missed couple of major factors for the power used by Amtrak. First and foremost, the host railroads don't want a passenger train fouling their tracks...if one breaks down, the other should be able to haul it rather than Amtrak sending another loco a thousand miles or the host railroad having to find something and crew to do it. Second, Amtrak does't want to have to go a thousand miles for a back up locomotive and doesn't want to pay the host road for the use of a locomotive and for the rescue crew. Third, Amtrak itself has to move power around and much better to do in in a train going that way rather than sending it light with crew (which they might or might not have nor want to pay the host road for). Fourth, no turning facilities...if it ain't push pull, then they can at least run the power around the train....providing the units are back to back and not elephant coupled. I think these are probably more the reasons for two locos than what you have proposed.
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Henry thanks for the jab. That is what happens when there was no proof reading. Have added item #16 & 25 and will add in any others that any poster notes.
blue streak 1 There is a preception by potential passengers that any mode of transportation that can operate on time is doing a good job.
Streak,
As one railroad passenger I would not reduce transportation success to simply operating on time. However, when there is significant and repeated lateness then I would conclude the operator is no doing a good job.
John
New loco specs published
http://www.highspeed-rail.org/Documents/loco-spec-reva-2012jul10.pdf
Highlights ;
1. 125 MPH capable pulling 5 cars 1 loco ( no grade specified so suspect level ? )
2. AC traction motors
3. capable of running 1 axel brand new and another axel full wear indicating that separate inverters for each axel ?
4. either 4 or 6 axels
5. capable of operating push pull cab cars or loco at each end.
6. Provision for future ECP braking.
7. minimum of unsprung weight
8. Both cab signaling and / or PTC.+ ALL systems now used
9. HEP 600 kw cannot use more than one source ( no paralleling of two locos )
That's all I remember
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