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What does SMEE mean?


Maserati7200

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S -> Straight Air, as opposed to A (Automatic). Straight air

systems are characterized by a trainline in which

air pressure is proportional to the degree of braking

effort desired. Automatic systems use a trainline

in which the braking effort call is proportional to

the difference between the trainline pressure and the

reference pressure.

 

M -> Motor car equipment. As opposed to "T", trailer car. "M"

schedules generally include compressor, reservoir and

motorman/engineer's brake valve, in addition to the

equipment that comes with "T" schedules (cylinder(s),

control/triple/universal valve, aux reservoir (if applicable))

 

E -> Emergency. The addition of an emergency trainline pipe makes

the straight air system failsafe. "A" (Automatic) schedule

systems accomplish this with a single pipe. Schedule

"SME" was a common streetcar apparatus where trailers

(schedule STE) were hooked on for rush hour capacity.

The emergency pipe is also called the Brake Pipe.

 

E -> Electropneumatic. This means that electric trainline circuits

are used to speed the propagation of the brake request

signal through the train. On NYCT equipment, these trainlines

are called "A" and "R" wires. There is also an "EMV" wire

which provides an electric emergency application.

Without the last E, SME would be too unresponsive for the

500-600' train lengths that NYCT operates.

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S -> Straight Air, as opposed to A (Automatic). Straight air

systems are characterized by a trainline in which

air pressure is proportional to the degree of braking

effort desired. Automatic systems use a trainline

in which the braking effort call is proportional to

the difference between the trainline pressure and the

reference pressure.

 

Yup correct. I'll add to this by giving an example for all of you so that it makes sense since it's complicated. Compare SMEE to an AMUE system (arnines, Lo-V). AMUE is an automatic system. SMEE is Straight Air.

 

AMUE: you grab brake, the air pressure goes down from the standard pressure. the difference is your braking effort. If your air pressure goes from (made up numbers) 100 lbs. to 85 lbs., you took 15 pounds of brake to stop the train.

 

SMEE: you grab brake, the air pressure goes up. If you grab 15 pounds, your gauge will go to 15 pounds...release and it will go back down again.

 

Mechanically the two systems are very different but that's WAY to much to put in here...

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SMEE = Self-Lapping Mechanical Electrical Equipment. I had posted it a while back, and scanned what it means, from my Operations Manual for T/Os........

 

The concept is what was posted by the others..........

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