MNRR Dual Mode Chargers discussion

[Touchdowntom9]

Time to restart the discussion.

Man those are quiet. Assume that’s the benefit of using 3rd rail whenever available. Fantastic stuff

 

[Dutchrailnut]

Keep in mind currently only 302 has third rail gear installed on its trucks. for 301 it is not available yet.

 

[daybeers]

 

[west point]

Noticed that the loco is slightly narrower than the passenger cars.

 

[MARC Rider]

Are these dual mode locomotives engineered to allow operation at full speed when third rail is available?

 

[PVD]

If I recall correctly, 80 mph operation on 3rd rail power is possible, which would be consistent with the M-7 EMU operation.

 

[west point]

If I recall correctly, 80 mph operation on 3rd rail power is possible, which would be consistent with the M-7 EMU operation.

IMO there are 2 separate factors for max speed.
1. the actual mechanical limit when shoe is contacting the third rail. Have no idea but over running and under running might have different values. the design of the shoe will be determined by the current draw.
2. Electrical draw is the other. The number of amps each of 2 shoes can draw. EMU shoes draw much less amps since each car is drawing only power for its car. So, MNRR locos current draw is much greater per shoe. The max current draw may depend probably on amount of surface contact that the shoe places on the rail. the post that says the shoe design is different and only 4 are on 301 (2 each side) since more have not been delivered. It may be that they are just prototypes subject to change.

What could really complicate the use of 3rd rail is if one shoe fails out of the 4

 

[PVD]

IMO there are 2 separate factors for max speed.
1. the actual mechanical limit when shoe is contacting the third rail. Have no idea but over running and under running might have different values. the design of the shoe will be determined by the current draw.
2. Electrical draw is the other. The number of amps each of 2 shoes can draw. EMU shoes draw much less amps since each car is drawing only power for its car. So, MNRR locos current draw is much greater per shoe. The max current draw may depend probably on amount of surface contact that the shoe places on the rail. the post that says the shoe design is different and only 4 are on 301 (2 each side) since more have not been delivered. It may be that they are just prototypes subject to change.

What could really complicate the use of 3rd rail is if one shoe fails out of the 4

I'm basing my numbers on the published specs

 

[Dutchrailnut]

The SC42-dm has 8 third rail shoes, 4 on each side

 

[west point]

The SC42-dm has 8 third rail shoes, 4 on each side

That certainly changes the dynamic. I stand corrected. Any specs on Max current rating of each shoe? Unfortunately, too late to edit my post. Did try.

 

[Amtrak25]

Can those shoes move to flip out of the way or operate on over-sliding 3rd rail ?

 

[Dutchrailnut]

No the shores are not flippable but a dual sided shoe same as on M-8's can be used not ordered at this time.
Each shoe has a 700 amp fuse.