Passenger Trains > Questions: Caltrain electrification

Wire is up for a couple miles Millbrae to
just south of San Bruno. For that distance,
is it ready to go? Flip a switch and the
AEM7 could run under it?

No wire north of San Bruno -- what each
tunnel has, tho, is a steel? beam (maybe
4 inches by 4 inches) above each track centerline
for the length of the tunnel (and a few feet
more at each end). What for?

Remember what PRR catenary looked like?
The catenary wire at the top suspended a
messenger wire (or whatever it was called)
that suspended the contact wire or running
wire, or whatever it was called. Nowadays,
we apparently don't need the messenger wire --
just two wires now run above each track.
What's changed? Why is two wires enough now?

Is the contact wire aluminum or copper? 

Railpax71 Wrote:
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> Is the contact wire aluminum or copper? 

Bronze (copper alloy). 25kV voltage has twice the power capacity in the same wire as the 12kV PRR system.



Edited 1 time(s). Last edit at 06/23/22 15:38 by prr60.

The old second messenger wire isn't necessary in modern stuff for two reasons - higher voltage and the constant tension design.  The second messenger (I think the PRR called it the "auxilliary conductor") used to provide extra current-carrying capability, which is largely rendered unnecessary with the move to 25kV which cut the current by ~60% over the PRR's 11kV system.  The other thing it offered was additional support and stiffness for the contact wire, but now keeping the contact wire under constant tension largely does the same thing.

I assume the bar you see is probably rigid catenary.  Basically it's an aluminum extrusion with the copper or phosphor bronze contact wire inserted in a slot at the bottom.  They're frequently used in tunnels and other tight quarters where there isn't the space needed to mount the usual arms and string support and contact wire.

Well, the big question continues:  When will testing possibly begin?

 

I delivered a sizeable LTL (Less-Than-Truckload) electrical parts shipment to this contractor about 8 months ago, and they told me "it will be some time before we're done.  Not enough money was budgeted, and costs are increasing....".  That's what I heard on the ground.

Coach



Edited 1 time(s). Last edit at 06/23/22 23:46 by coach.

coach Wrote:
-------------------------------------------------------
> I delivered a sizeable LTL (Less-Than-Truckload)
> electrical parts shipment to this contractor about
> 8 months ago, and they told me "it will be some
> time before we're done.  Not enough money was
> budgeted, and costs are increasing....".  That's
> what I heard on the ground.
>
> Coach
Cluster F.... this is why we don't have high speed trains here. To much government red tape and cost to make it worth it, and poor management, but someone is getting rich.

Posted from Android

Believe the test track will be near CEMOF (San Jose) on a side track that runs parallel to the mains heading towards SF

Segment 4 between Santa Clara and Tamien is scheduled to be energized second half of this year.