Acela vs. Regional

[Dinker]

Why is that the Acela only hits 150mph between Boston and New York, while the difference in travel time between an Acela an a Regional is far greater NYP-WAS than it is NYP-BOS.? As I understand it, the Regionals can make it up to 125mph - what's the Acela top speed NYP-WAS? Do the Acelas accelerate a lot faster and this explains the difference? Or do the time differentials mostly have to do with the amount of station stops?

 

[AlanB]

Acela in a few areas can hit 135 south/west of NY. The rest of the time differences are due to fewer station stops, faster acceleration, and shorter dwell times at the few stations that Acela does stop at.

 

[PRR 60]

Why is that the Acela only hits 150mph between Boston and New York, while the difference in travel time between an Acela an a Regional is far greater NYP-WAS than it is NYP-BOS.? As I understand it, the Regionals can make it up to 125mph - what's the Acela top speed NYP-WAS? Do the Acelas accelerate a lot faster and this explains the difference? Or do the time differentials mostly have to do with the amount of station stops?

Between New Haven and Westerly RI the route curvature provides significant advantage to the Acela and the ability to tilt in the curves. The Acela in some cases is permitted speeds 15mph greater through the curves than the Amfleet trains. When you couple this with the time savings from shorter acceleration and deceleration times, the Acela makes up a lot of time in this section of the route.

 

[battalion51]

There's also a big difference in the weight to horsepower ratio since the Acela pulls 6 cars with 12,000 horses, while Regionals pull 7-8 cars with 7,000 horses. The big difference is in the tilting system. I don't have my book with me, but the Regionals have to do a lot more slowing down for a lot more curves.

 

[Guest]

I don't know if this is true or not, but it seems that Acelas have priority over regionals. Acelas rarly let people pass, but regionals get passed a lot. I've had conducters say as much, too. If they fixed the tracks, the regional could probably go just fast as the Acela is doing now.

 

[AlanB]

Why is that the Acela only hits 150mph between Boston and New York, while the difference in travel time between an Acela an a Regional is far greater NYP-WAS than it is NYP-BOS.? As I understand it, the Regionals can make it up to 125mph - what's the Acela top speed NYP-WAS? Do the Acelas accelerate a lot faster and this explains the difference? Or do the time differentials mostly have to do with the amount of station stops?

Between New Haven and Westerly RI the route curvature provides significant advantage to the Acela and the ability to tilt in the curves. The Acela in some cases is permitted speeds 15mph greater through the curves than the Amfleet trains. When you couple this with the time savings from shorter acceleration and deceleration times, the Acela makes up a lot of time in this section of the route.

Bill, he asked why Acela was so much faster between NY and DC, so I'm not sure how the curves between New Haven and Westerly will have much effect on the running times south/west of NY. :lol:

 

[rmgreenesq]

I don't know if this is true or not, but it seems that Acelas have priority over regionals. Acelas rarly let people pass, but regionals get passed a lot. I've had conducters say as much, too. If they fixed the tracks, the regional could probably go just fast as the Acela is doing now.

I'd agree that the Acela has priority over a regional. A regional train leaves BOS at 6:05 am and the Acela leaves BOS at 6:15 am. They meet at PVD with the regional train arriving first. The regional is held so the Acela can leave first. I understood the value of the upcharge for the Acela while sitting on a regional train in PVD.

Rick

 

[PRR 60]

Bill, he asked why Acela was so much faster between NY and DC, so I'm not sure how the curves between New Haven and Westerly will have much effect on the running times south/west of NY. :lol:

Well, maybe they feel so good from having such a nice run from Boston that they keep up the pace heading to DC? Nice try, eh. I'll try reading the entire question next time.

NYP-WAS: slightly higher top speed, tilt advantage, and fewer stops. Each stop adds about four minutes (decel, dwell, accel). So just two or three extra stops can add significantly to the end-point run time.

 

[battalion51]

An Acela is always going to have priority over a Regional. Acela's are high speed, high priority trains. The Acela clientelle is typically the Business clients on time sensitive business. Amtrak does not want to **** off this very critical piece of its clientelle because they could easily jump ship and go to the airline shuttles.

As far as fixing the tracks is concerned they have done a lot to straighten out and ease curves already, so there's little that can be done in that department. There's also the simple fact that the most you are ever going to get out of a Regional trainset is 125 because that's all the cars and engines can do. If track conditions were improved any more odds are Acela speeds would go up too. There will always be a time disparity between the two runs.

 

[Dinker]

Thanks for the all the answers! Thing is, I'm still not sure I've understood - the question was probably a bit unclear:

NYP-BOS

Acela max speed: 150

Regional max speed: 125

Time difference b/w two: 20-25 minutes

NYP-WAS

Acela max speed: 135

Regional max speed: 125

Time difference b/w two: 40-45 minutes

The NYP-BOS is slightly, but not significantly longer than the NYP-WAS. Given the greater difference in top speeds in NYP-BOS, one would expect the time difference also to be greater in NYP-BOS. It's not, so my question was 'why?'

Part, but not all, of the answer is of course that 15 mph does not make that huge of a difference, especially considering that the trains don't get that fast for much of their route but there still should be something else going on here to explain why the time difference northend is SMALLER than the time difference southend, right?

Alan, am I correct in understanding your answer that "the time differences are due to fewer station stops, faster acceleration, and shorter dwell times at the few stations that Acela does stop at" to be mean that NYP-BOS these factors are less significant than NYP-WAS? That would make sense. Or, Battalion, did you mean that Regionals have to stop comparatively more often than Acelas NYP-WAS than NYP-BOS? Again, that would explain the difference. I think this is what PRR60 was getting at in his last post. Otherwise, acceleration, like priority in dispatching, would be constant across the route and the only variable would be top speed, which would mean that NYP-BOS should have a greater time difference. Thanks for all the answers - always impressive how much knowledge and enthusiasm there is on the forum.

 

[gswager]

Acela has fewer station stops than Regionals. That's why is makes a lot of difference in time.

 

[Dinker]

Acela has fewer station stops than Regionals. That's why is makes a lot of difference in time.

Yes, but does it have even fewer stops than a Regional south of New York than north of New York?

 

[Guest]

Acela has fewer station stops than Regionals. That's why is makes a lot of difference in time.

Yes, but does it have even fewer stops than a Regional south of New York than north of New York?

It would apear so. If both trains stoped at all possable stops, it would be 6 above, 7 below for the Acela, and 19 above and 15 below for the Regional.

 

[rmgreenesq]

An Acela is always going to have priority over a Regional. Acela's are high speed, high priority trains. The Acela clientelle is typically the Business clients on time sensitive business. Amtrak does not want to **** off this very critical piece of its clientelle because they could easily jump ship and go to the airline shuttles.

Especially after they have piad between $50 to $200 more than the regional for the privledge of riding in the Acela.

(edited to fix quote - AmtrakWPK)

 

[battalion51]

Thanks for the all the answers! Thing is, I'm still not sure I've understood - the question was probably a bit unclear:
NYP-BOS

Acela max speed: 150

Regional max speed: 125

Time difference b/w two: 20-25 minutes

NYP-WAS

Acela max speed: 135

Regional max speed: 125

Time difference b/w two: 40-45 minutes

The NYP-BOS is slightly, but not significantly longer than the NYP-WAS. Given the greater difference in top speeds in NYP-BOS, one would expect the time difference also to be greater in NYP-BOS. It's not, so my question was 'why?'

The why is because just because that top speed is 150 that does not mean that the train is cruising at that top speed for the duration of the trip. According to the '01 Timetable there are two segments totaling 18 miles (except for 2 curves on Track 1) that are rated for 150 MPH operation. 18 miles out of the 155 that Amtrak owns on the Boston-New Haven segment. Now the rest of the Speed for the majority of the run (not including curves and DSR's), 110, 125, 90, 85, 60, 85, 25, 40, 60, 70, 90, 95, 135, 65, 70, 135, 120, 110. Do the math. Now this does not include 56.5 miles of 90 MPH max running on Metro North, or the mere 3 miles of 100 MPH running on the Main Line from Harold to CP216.

 

[Dinker]

Thanks for the all the answers! Thing is, I'm still not sure I've understood - the question was probably a bit unclear:
NYP-BOS

Acela max speed: 150

Regional max speed: 125

Time difference b/w two: 20-25 minutes

NYP-WAS

Acela max speed: 135

Regional max speed: 125

Time difference b/w two: 40-45 minutes

The NYP-BOS is slightly, but not significantly longer than the NYP-WAS. Given the greater difference in top speeds in NYP-BOS, one would expect the time difference also to be greater in NYP-BOS. It's not, so my question was 'why?'

The why is because just because that top speed is 150 that does not mean that the train is cruising at that top speed for the duration of the trip. According to the '01 Timetable there are two segments totaling 18 miles (except for 2 curves on Track 1) that are rated for 150 MPH operation. 18 miles out of the 155 that Amtrak owns on the Boston-New Haven segment. Now the rest of the Speed for the majority of the run (not including curves and DSR's), 110, 125, 90, 85, 60, 85, 25, 40, 60, 70, 90, 95, 135, 65, 70, 135, 120, 110. Do the math. Now this does not include 56.5 miles of 90 MPH max running on Metro North, or the mere 3 miles of 100 MPH running on the Main Line from Harold to CP216.

Okay thanks, this (perhaps combined w/ more station stops for Regionals south of New York) is more or less what I'd figured must be the answer. Does this mean that if an Acela is alow to take a segment at 110, the Regional can also take it at 110, or do the two trains have different max. speeds for the same segment of track, even when that track is 125mph or below?

 

[x-press]

I guess I'm confused by the question. Acelas ARE generally much faster than regionals NY-Boston, and generally NOT much faster NY-Washington.

The fastest Regional NY-Washington that I found in a random look just now was 3:08, versus a 2:45 Acela. 23 minute difference.

The fastest Regional NY-Boston that I found was 4:03 (with most significantly longer), versus a 3:33 Acela. A 30 minute difference (again, with many trains having much higher differences).

Did I misunderstand the question?

JPS

 

[Dinker]

Yeah, I missed that 3h 5min Regional from NYP-WAS. I suppose it was a pretty dumb question.

 

[battalion51]

Okay thanks, this (perhaps combined w/ more station stops for Regionals south of New York) is more or less what I'd figured must be the answer. Does this mean that if an Acela is alow to take a segment at 110, the Regional can also take it at 110, or do the two trains have different max. speeds for the same segment of track, even when that track is 125mph or below?

Well it all depends on the curve. Let's look at some examples:


Key:

BS-Boston Sub (BOS-NHV)

HL-Harold Line (CP216-Harold)

PS-Philadelphia Sub (NYP-PHL)

WS-Washington Sub (PHL-WAS)

Cv-Curve

MP-Milepost

AT-Type "A" Train (Acela)

BT-Type "B" Train (All Amfleet)

BS Cv MP 102- AT 80 BT 70

BS Cv MP 135.9- AT 65 BT 60

BS Cv MP 171.7- AT 110 BT 95

The Harold Line has the same speeds for all passenger trains regardless of type

PS Cv east of Elmora- AT 55 BT 55

PS Cv MP 25- AT 100 BT 95

PS Cv west of Trenton- AT 95 BT 95

PS Cv MP 74- AT 100 BT 90

PS Cv MP 84- AT 65 BT 65

WS Cv MP 5- AT 100 BT 90

WS Cv MP 50- AT 105 BT 90

WS Cv MP 57- AT 110 BT 95

WS Cv MP 94- AT 50 BT 50

Now what's interesting is between New York and Washington different tracks have different curve speeds, the ones I listed are only examples (but at the same curve on the same track). So there really doesn't seem to be a method to the madness. To paraphrase Abe Lincoln, "All curves are NOT created equal."

 

[AlanB]

Now what's interesting is between New York and Washington different tracks have different curve speeds, the ones I listed are only examples (but at the same curve on the same track). So there really doesn't seem to be a method to the madness. To paraphrase Abe Lincoln, "All curves are NOT created equal."

That's because the tracks haven't been maintained to the same standards. In some areas one track is mainly used only by MARC. Amtrak only runs on it when there are problems. I also don't think that they've replaced all the wood ties with concrete yet down there, so that may have some effect on things too.

 

[x-press]

Yeah, I missed that 3h 5min Regional from NYP-WAS. I suppose it was a pretty dumb question.

Not at all, Dinker! It's interesting, actually, that there is so much variation between the "same" brands of service. My girlfriend randomly selected the slowest regional there is NY-Baltimore, making stops even at Newark, DE (along with everywhere else). When she got back, I explained the need to check running times; she never would have known, otherwise, and would have just assumed that all regionals were slow like the one she took.

Not too many years ago, every train on the corridor had a name (Merchants Limited, Senator), so they were a little easier to tell apart.

Best Wishes,

JPS