Window Question . . . why does Amtrak require split windows with a vertical mullion?

[BostonTrainGuy]

Checking out the specs for the new Amtrak cars at:

http://www.highspeed-rail.org/Pages/DocsSpecs.aspx

I have to ask why Amtrak requires two piece side windows instead of single panes?  The fastest trains in the world have one piece windows so it's not a strength issue.  Amtrak's old Turboliners and Talgos (foreign designs of course) both have single panes so it can't be an FRA requirement.   But the rest of Amtrak's existing fleet (excluding rarities like the high-levels and dome), and the proposed new designs above, all have the split design.  I think a one-piece window looks better, allows better viewing, and might be slightly less expensive to make and maintain.

Does anyone know the reason for this?

[travelingengineer]

Could it be that split windows are more easily removed in case of an emergency exit (car on side, upside down, tilted)?  Perhaps an elderly passenger would not have the strength to pull on the current red handle, pull out the rubber gasket, then open the window if it was large and heavy.

[oltmannd]

Gotta be cost.  Smaller windows are cheaper and easier to deal with.  As many as they change due to rocks......

[BostonTrainGuy]

But no regional/commuter rail agency uses that design, and I would think they would experience much more "urban-related" vandalism such as rock throwing.

(Also, it might be quite a challenge to hit a window on a 150 mph Acela as it blows by.) 

[henry6]

Is it because of vandalism or because North American standards are heavier than Eurpoean standards thus the added post support?

[oltmannd]

BostonTrainGuy

(Also, it might be quite a challenge to hit a window on a 150 mph Acela as it blows by.) 

 SIx 85' passenger cars take 2.3 seconds to go past.  That's plenty of time.

There is more window than space between the windows, so you'd have a much better chance of nailing a window than missing if you had the right elevation.  If you stood 50 feet away and threw a rock at 35 mph and started your toss as the locomotive passed, you'd hit the train in the middle of the second coach.

Breaking the windows is a bit more difficult.  A 35 mph toss of a small rock wouldn't do it.

[oltmannd]

BostonTrainGuy

But no regional/commuter rail agency uses that design, and I would think they would experience much more "urban-related" vandalism such as rock throwing.

 They also don't use the double glazing that Amtrak does.  Amtrak uses glass on the outside and polycarbonate on the inside.  I know the SEPTA Silverliners use (or at least, used)only single glazing of polycarbonate.