T electrics on NEC?

Discussion relating to commuter rail, light rail, and subway operations of the MBTA.

Moderators: CRail, sery2831

Re: T electrics on NEC?

Postby AEM7AC920 » Sat Aug 04, 2012 3:59 pm

Maintaining diesels regardless of who makes them is still another ball park vs electrics. We are getting into comparing apples and oranges.
Posts: 2582
Joined: Fri Mar 12, 2004 4:51 pm
Location: Unkown.....

Re: T electrics on NEC?

Postby F-line to Dudley via Park » Sat Aug 04, 2012 4:11 pm

diburning wrote:Double stacks CAN run under catenary if the catenary is high enough, BUT bridges are a problem. The catenary has to be lowered to go under bridges, and with bridges that can barely fit double stacks as they are now, it would require considerable cost and effort to raise the bridges or undercut the tracks to accommodate catenary AND double stacks at the same time.

22' for the DS clearance + 3 ft. for under-bridge clearance for 60Hz/25kV wires = 25'. The upper limit the pantographs on any Amtrak electric can stretch is 25'6". Yes, it is done on the Keystone line today and on some freight yards that intersect the NEC and require crossing under the wires.

For the Worcester Line it's only Worcester-Westborough yard where this comes into play. These are the bridges:
-- Rt. 135, Westborough
-- Otis St., Westborough (east of station)
-- Fisher St., Westborough (west of station)
-- Pine St., Grafton (at station)
-- Shrewsbury St., Grafton (west of G&U interchange)
-- Hamilton St., Worcester
-- Plantation St., Worcester

That's it. Plus I-290 @ Worcester Station and yard, but that one already looks significantly taller than 25' over the tracks. This stretch of Worcester Line has a lot more rail bridges than road bridges. And if these are up-to-spec today for 22', coming up with +3 ft. is not too difficult. You can usually undercut the railbed to achieve that. Getting to 22' first from all manner of nonstandard clearances is the hard part. I don't think it would be a blocker, or a deal-breaker if they were already willing to spend on the electrification infrastructure.

Now, if there were ever a desire to bring DS's east of Westborough to Framingham or Boston via the Franklin Line, then I think there's no way that's possible unless the line is tri-tracked with one unpowered freight track. Too many sub-DS bridges today that would require lots of work just to achieve the 22' clearance sans wires, nevermind the 25' with wires. But Worcester-Westborough...I don't think there are huge blockers here. West on the B&A to Springfield is a different story. I don't see how that's going to work without a lot more $$$ for a much lower-return project than east-of-Worcester.
F-line to Dudley via Park
Posts: 7105
Joined: Fri Mar 11, 2005 7:26 pm
Location: North Cambridge

Re: T electrics on NEC?

Postby Fan Railer » Sat Aug 04, 2012 10:02 pm

ferroequinologist wrote:
boblothrope wrote:Dual-modes generally have worse performance than either diesels or electrics.

Is that just because of the extra weight/lower power to prevent excessive weight?

In essence, yes. A more powerful traction transformer is going to be heavier. When you stuff one or two diesel prime movers into the locomotive body, you sacrifice the extra weight play room you would have in a straight electric, and thus, you will have a much less power from the traction transformer. Case in point --> ALP-46A vs ALP-45DP.
Fan Railer
Posts: 2156
Joined: Wed Sep 03, 2008 9:32 pm

Re: T electrics on NEC?

Postby DutchRailnut » Sun Aug 05, 2012 7:47 am

ALP 45DP has almost same HP in electric as a 46, as for diesels their inside locomotive the transformer in both locomotives hangs under frame.
If Conductors are in charge, why are they promoted to be Engineer???

Retired Triebfahrzeugführer
User avatar
Posts: 21176
Joined: Thu Mar 11, 2004 8:02 pm
Location: released from Stalag 13


Return to Massachusetts Bay Transportation Authority (MBTA)

Who is online

Users browsing this forum: No registered users and 6 guests