Does anyone know if the F40s that Amtrak used were equiped with dynamic brakes?

Brian


btamper@hotmail.com

Amtrak's F40PH locos were delivered with dynamic braking, and as far as I know they retained them until retirement. There are some F40's out there without dynamics--CalTrain's for example.


LNER4472-NOSPAM-@bcpl.net

The original Caltrain F40PH locos were built without dynamic brakes, (called "blended brakes in Caltrain information) but most (but not all) of the fleet had them installed durring their mid life rebuilding 4-5 years ago and all subsiquent orders have included them.

Randy Hees

http://www.spcrr.org
hees@ix.netcom.com

What about gearing? Were all the F40PHs geared the same, say for up to 80mph or were there any that were geared lower for use in steeply graded railways? If there was a difference, how can you tell?

Brian


btamper@hotmail.com

> What about gearing? Were all the F40PHs
> geared the same, say for up to 80mph or were
> there any that were geared lower for use in
> steeply graded railways? If there was a
> difference, how can you tell?

As built, all Amtrak F40PH's were geared for 100-mph operation (which I *think* is the 57:20 gear ratio); many were rebuilt for 110-mph operation (56:21?) on Empire Service and other such trains. Second-party owners, such as the Canadian Atlantic, have locos re-geared for freight duty. I assume commuter locos owned by Metra, CO Transit, CalTrain, etc., have lower-speed gearing.

If you're talking to Amtrak personnel or a private party about acquiring an F40, you have no business dealing with anyone that can't tell you the specific ratio of the specific loco in question; you should have no need to tell them apart. I seem to recall that the gear ratio was among the numbers stenciled down along the frame at the front near the nose.

LNER4472-NOSPAM-@bcpl.net

Dynamic brakes and blended dynamic brakes are kind of first cousins. Blended dynamic brakes uses the locomotives dynamic brake to replace the locomotive's friction brakes while the rest of the train continues to rely on the particular friction brakes employed on the cars. The blended dynamic only engages after the electronics in the system are sure the friction brakes are working on the locomotive (i.e., it sees brake cylinder pressure). After the friction brakes come on, the electronics blend the dynamic into the mix and reduce the friction brake pressure. As speed reduces, the system brings the friction brake pressure in the locomotive up as the dynamic effect reduces. Plain old dynamic brakes is an engine-only thing and is employed in place of both locomotive and train brakes. You'd be surprised the number of folks who don't understand the difference.

prr8404@aol.com

Thank you for the excellent explanation.

Tom