Several signal/equipment/operation questions

It can get irritating (take it from someone who has taken many a cabride in an M-7.) I do believe the interval is 25, but it resets itself if the throttle is moved, so some conductors move that to avoid the noise. Annoying, yes, but it keeps the engineer alert, and that can't be a bad thing.

Yes, the alerter timer is 25 seconds on the LIRR M-7 cars.
The alerter can be satisfied by moving the acknowledging joystick, moving the Master Controller handle through the "Coast" position, or sounding the horn with sufficient amplitude to "make" the pressure switch associated with it.
If one of these things is not done, the brakes will apply 15 seconds after activation of the alerter.

The M-7 does have a deadman pedal, but it is not used unless the alerter function is disabled due to defect.

Tom

does the alerter on an M7 have a bright light that flashes as well as the beeping sound, or does it just sound with no light?

There is a fairly large indication that "lights up" on the Train Operator's Display that says "Alerter". The noise is the main indicator. It gets gradually louder as time passes without acknowledgement.
The Alerter noise "deedoodeedoo..." differs from the downcode and/or overspeed noise which is a loud "beepbeepbeepbeep!!".

Tom

Interesting that LIRR and Metro-North have the same alerter specs. Since they ordered their M-7A's a little different than LIRR. Cab signal aspects are different and seating arrangement is opposite ours.

Wow, this was the first time I've been able to post a reply, but the information is really informative and interesting!

Now, during braking in an overspeed, the ATC package must see a minimum deceleration rate attained and maintained until the overspeed is cleared. At that time, the Engineer can reset the P-wire, release the brakes, and resume operation. If the minimum deceleration rate is not maintained continuously while braking in an overspeed condition, the brake pipe will vent, putting the train into "Emergency Brake Application" ("Dumping").

I was wondering, if the train automatically brakes, it will continuously decelerate until it reaches an allowable speed. How then could the minimum deceleration rate not be continuous?

Also, because the alerter and audible warning device are two different systems with different sounds, do they need to be reset by different buttons?

I remember when riding M1/M3's at the front, I would hear bells from the cab. Is this the audible warning device?

The MAS of the diesal equipment is 65 even in places where the MAS for MU's are 80?

I also had a few more questions:
1. I know that the M7's have a slide controller for combined braking and throttle. Does this handle have to be held laterally, in order to avoid an emergency brake application (dead-man's)? Do the M1/M3's come with separate brake and controller handles? Do the DE/DM's/C3's have a setup consisting of throttle, train brake, loco brake, and dynamic brake? The M1/M3's have control stands, while all the M7/C3/DE/DM have 'desktop' controls?

2. Does the ATC/ASC give a restricting type of aspect for reversing moves of the train?

3. Do the DC motors of MU's run on 3rd rail voltage(750V)? What is the voltage of AC motors for the M7's and the AC motors of the DE/DM's? The amount of current running through the motors determines speed? Can inverters be used to step up/step down/change voltage on trains or does a transformer do that?

4. Is there ever full 750V running through couplers in the trainline between two cars of a married pair or between MU cars in general?

5. Other than the AM/PM rush hour Harold Protect (they are specifically two MP15's?), does LIRR keep protect engines elsewhere? I read from another post that they need compromise couplers for only M7's and they have the same couplers as M1/M3's, allowing for only brake control of M7's and full brake/electrical control for M1/M3's. How do protect engines work for the diesal trains?

6. I also read that they run non-overhauled M1's in the middle of the train due to older cab signal systems? Is this true?

Kyle

Kyle,

I'll answer a few and leave the rest to the others.

DC Motor speed is controlled by voltage. AC motor speed is controlled by frequency.

An ASC penalty application will continue until the proper speed is reached or the train will dump if the reduction is not sufficient.

In one post, the operation of the M7 alerter was discussed. The audible warning device is acknowledged by brake application and rate.

M1/3 audible warning device is the bell that sounds like a telephone.

ASC does not operate when the train is operating in reverse as seen from the motorman's seat.

The Harold protects are the only regularly assigned protect jobs. During bad weather, special events, protect engines are placed in other locations such as Valley, Shea etc. A protect engine can couple to anything using compromise couplers. Two engines are equipped with M1/3 couplers.

An M-1 in good condition can operate anywhere in a train. If it has a ASC failure, bad coupler, etc, it may be placed in the appropriate place to remain in service.

There is no 750 Volt trainline. There is a 750 Volt buss jumper between the B Ends of the married pair, however. There is no 750 in the coupler.

Hope that answers a few of your questions...

Anyone please be free to correct any details I may have missed.

Clemuel

The DC motors on the M1/3 cars are controlled by the old, traditional 'series parrallel' system.

When starting out, regardless of controller position, a (realatively) large resistance is inserted in series with all the traction motors (all the motors in a single car) - which are in series. As the train accelerates, the cards in the control group operate the controller to slowly cut out the various resistances. I think this is done by shorting the resistors - those in the know canfill in the missing details here. After a while, the car has all of the resistors out of the circuit. If the controller's in P1 - nothing more happens. But if it's in P2 or higher, the controller now rearranges the motors into two groups in parrallel - each truck's motors are still series, but both trucks are now parrallel. The (realatively) big resistance is put back in series with this, and then slowly cut out. If you're in a car with a dead HVAC system, you can hear the controller making a 'clunk' every time it steps. If you're really good, you can feel the slight jump in acceleration as this happens. Once full parrallel is reached, in P2, nothing more happens. In P3 or higher, a 'shunt' resistor is placed accross the field windings, and then if the controllers in P4, this gets reduced a bit in steps. ISTR that P3 is like 25% shunt, P4 is 50% shunt. Or something like that. At this point, the train reaches a 'balancing speed' at which it's no longer possible to speed up.

The full 750V is accross each truck's motors, so each motor's seeing 1/2 that.

AC motors are different. First, the DC is regulated and filtered in what's called a 'DC link". Then, via a '6 pack' of IGBTs it is 'chopped' into AC. This is what causes that whine M-7s make. The chopping is via pulse width modulation. The controlling computer cn make pretty much any frequency up to 60hz and any voltage up to the 480 or so the motors run on. Now, the cool part is that it can also 'regenerate', which means the motors generate electricity like generators. And they can do this to near 0 rpm (some advanced inverters can even provide holding torque at 0rpm.). Theoretically, the m-7 doesn't need the air brakes for much more thanscrubbing the tread and staying still in stations...

The excess power getting regen'd into the DC link causes the link voltage to rise, and as it goes up, the brake unit - basically a bank of IGBTs in series with a resistor, accross the link - activates to keep it down. Since the HEP system tends to be tied to the DC link, this means that during braking, the train is effectively using NO power from the third rail at all (NJT MUs pretty much can't be detected on the line durring coasting or braking). It's theoretically possible to send it out the third rail, but since it'll just hit the substation and do no good there, I don't think the LIRR does this. The NYCTA does because the chances of another train being on the same sub are so high - and that train can use the power. of course, you could always stick a dump unit or inverter at the sub station and then it could absorb the power.

There are no transformers involved here. A transformer won't work on DC.

The HHP-8s and ALP-46s can also regen back into the wires. The HHP-8 has brake grids also, the '46 doesn't - it falls back to friction braking if the catenary can't recieve the power (no biggie on an AC system, since the substations go both ways - basically, a phase break or no power situation is where it happens, both cases where you're either not braking, or using the emergency brake which negates the regen on the 46 anyway, I think). I have the main power schematics (minus the inverter/converter details - it's really the overview though it does show the low side tap changing and all) on the '46 somewhere in my office - they show no braking unit or resistors in the DC link at all (save for the C-R filter). There's no brake grids shown in the layout of the thing either. The HHP-8 has brake grids - they're on the roof hiding behind the infamous roof covers.

I was wondering, if the train automatically brakes, it will continuously decelerate until it reaches an allowable speed. How then could the minimum deceleration rate not be continuous?

Wheel slide during braking is usually the culprit that messes up the detection of deceleration.

Also, because the alerter and audible warning device are two different systems with different sounds, do they need to be reset by different buttons?

Alerter can be satisfied by moving acknowledge joystick, sounding the horn loudly, or moving Master Controller to "Coast" position briefly.
Downcode or overspeed must be acknowledged with the acknowledge joystick.

I remember when riding M1/M3's at the front, I would hear bells from the cab. Is this the audible warning device?

Yes.

I know that the M7's have a slide controller for combined braking and throttle. Does this handle have to be held laterally, in order to avoid an emergency brake application (dead-man's)?

No, there is normally no deadman feature on the M-7. The Alerter supplants that system and I believe that is actually the FRA preferred system to use. The M-7 deadman pedal is only used if the Alerter function is disabled.

Do the M1/M3's come with separate brake and controller handles?

No. The controller handle does power, coast, and braking.

Does the ATC/ASC give a restricting type of aspect for reversing moves of the train?

Yes. Train direction is input to the Speed Control systems. Different equipment types will do it in different ways, but the net result is no code is present while in reverse.

Do the DC motors of MU's run on 3rd rail voltage(750V)?

Yes. Nas covered the rest of this.

What is the voltage of AC motors for the M7's and the AC motors of the DE/DM's?

In AC propulsion, both voltage and frequency vary. The propulsion inverter is called a VVVF (Variable Voltage Variable Frequency) device for that reason. The computer figures out what voltage and frequency is currently needed.

Is there ever full 750V running through couplers?

As Clem said, no. 750VDC buss line is contiguous to a married pair for all our EMU cars. There is no electrical coupler between the 2 cars of a married pair. Intercar jumpers carry all trainlines, battery power, 220VAC, and 750VDC (and 110VAC for M-7 only) between cars of the married pair. Electrical couplers are only on the front ends of the cars.
As mentioned above, yes there is 750VDC continuity between the cars of the married pair.

NOTE TO JERSEY MIKE:

The only territories that still operate under Rule 251 are Bliss to Jay (lower Montauk branch, Nassau to Locust on the Oyster Bay Branch and Babylon to Y on the Montauk Branch. Port Jeff is all 261.

"The MAS of the diesal equipment is 65 even in places where the MAS for MU's are 80?"

I guess the GP38s were only allowed 65, but apparently the DM/DEs are allowed 80.

"...the AM/PM rush hour Harold Protect (they are specifically two MP15's?)"

Two SW1001s-- each with a 1000 hp V-8 instead of the 1500 hp V-12 in an MP15.

SK2MY wrote:NOTE TO JERSEY MIKE:

The only territories that still operate under Rule 251 are Bliss to Jay (lower Montauk branch, Nassau to Locust on the Oyster Bay Branch and Babylon to Y on the Montauk Branch. Port Jeff is all 261.

True if you are only talking about 2 tracks. Otherwise don't forget about PD to MY on the Montuak and KO2 to GY on the Mainline

When traveling through Jamaica I have noticed the following. It appears that some layover MU consists have only their Blue ASC indicator light illuminated. Neither the amber or red parking break lights appear to be illuminated.

My question is: Is it possible for a train to be stopped, without the break being applied or parking break set?


Sometimes when traveling past Hillside, I have seen MU consists with their interior flourescent lights off. Are these trains actually powered down? Or are the lights simply turned off? Do electric trains ever get powered down? Aside from maintenance.

Thanks.....

An MU train can be stopped without brakes applied, but it is very unlikely. If you see a train in a yard it almost always will have a hand brake or at very least, the service brakes applied.

For an MU train to stand with brakes released it has to be attended, the brake pipe charged and the engineer releasing the brakes. Or it has to be dead with no air in the system. That seldom happens.

Trains are nearly always kept live. In some places, when laid up on weekends the inverters or motor alternators are turned off but this is the exception. Usually the lights are just turned off. The only exception may be in some shop areas, when work is being done.

Clemuel