What's with the Acela pans?

[Acela150]

In pictures i've noticed that all Acela sets run with the front pan raised not the rear. What's the deal? Is it a new policy?

Stephen

 

[Joel N. Weber II]

I think when operating near the speed limit of constant tension catenary, having a second pantograph raised can lower the speed that the overhead wire can cope with. Not sure if that's also true of the style of catenary used south of New York City and in the non-upgraded sections of Metro-North territory (which is where the Acela actually does operate close to the catenary's speed limit).

 

[Acela150]

I put this wrong. Both Power Cars have the front pans up.

The pans used to run like in the picture now the other one is up.

http://acela150kid.rrpicturearchives.net/s...aspx?id=1284400

Now they run as seen in the picture.

http://chuchubob.rrpicturearchives.net/sho...aspx?id=1525400

Stephen

 

[AG1]

I put this wrong. Both Power Cars have the front pans up.
The pans used to run like in the picture now the other one is up.

http://acela150kid.rrpicturearchives.net/s...aspx?id=1284400

Now they run as seen in the picture.

http://chuchubob.rrpicturearchives.net/sho...aspx?id=1525400

Stephen

In my old eyes it appears that the rear pans are used on both sets. One is hinged forward and the other is hinged back.

 

[battalion51]

It might have something to do with the side the angle of the pan is on. Look at this picture of a pair of AEM-7's. The Acela pan's are probably mounted the other way around. They probably want the wear on the wire to be consistent regardless of the type of train pan that's hitting it.

 

[Aegrotatio]

In pictures i've noticed that all Acela sets run with the front pan raised not the rear. What's the deal? Is it a new policy?
Stephen

I know the running lights are probably wrong but maybe one train is going in the opposite direction, or maybe there was a pantograph failure in some of those pictures? Perhaps they want to wear the graphite strip more evenly.

One thing I learned about the different catenary systems is that in moder catenary like constant-tension and the conventional Metro-North catenary the wire sways back and forth in relation to the track, spreading the wear across the strip. In PRR territory the old catenary grooves into a relatively small area compared to the newer parts of the system.

 

[Ryan]

It might have something to do with the side the angle of the pan is on. Look at this picture of a pair of AEM-7's. The Acela pan's are probably mounted the other way around. They probably want the wear on the wire to be consistent regardless of the type of train pan that's hitting it.

Both power units (Acela and AEM-7) have 2 pans that angle in each direction. I looked for a good overhead view of the Acela that showed this, but couldn't find one.

 

[battalion51]

 

[Ryan]

Perfect shot. On Acela the two pans are right next to each other, farthest away from the pointy end, but mounted in the same arrangement.

Now I know that there have been some switches in policy over which pan is put up (front or rear) but currently the usually run with the rear pan up (which is more better because if the pan catches the wire and everything comes crashing down, in theory the front pan will be ahead of the mess and will remain undamaged, or so I've read).