OK, This should be No 1000 - So ask me a Technical Locomotive Question

[M636C]

Guys,

I'm worried about how much time I've wasted making postings on this Forum (mainly) and I've realised that they have generally been technical reponses to locomotive questions.

So here is an invitation to ask any questions you haven't asked yet!

Peter

[vsmith]

OK how many locomotives does it take to screw in a lightbulb?

Congrates on the four star promotion!
[bday][bday][bday][bday]

[Kozzie]

Peter - Well done! from your down under colleague! [:)]

I knew it wouldn't be long! [:)]

Keep 'em coming!

Dave

[mloik]

QUOTE: Originally posted by M.W. Hemphill

Here's your question:

Are you ready?

Why?

Mark,

Very good! Reminds me of the last episode of "The Prisoner".

Michael

[kolechovski]

Very good...here's a question about running in the red...what causes negative amps?

[Junctionfan]

I haven't asked this at least but what does the automatic brake do and what are the positions? I see things like SV and RL on the thing and don't know what they all do or stand for.

[Anonymous]

QUOTE: Originally posted by M.W. Hemphill

Welcome to the four-star time-wasting club!

Here's your question:

Are you ready?

Why?

Because!

Is there a limit to how manu locomotives can be MU'ed? Do they need to be some what similar in performance and setup?

Congrats on the 4th star.

[M636C]

QUOTE: Originally posted by kolechovski

Very good...here's a question about running in the red...what causes negative amps?

Is this question related to the flow of electrons being opposite to the conventional flow of current, or is it a reference to motors acting as generators?

Peter

[M636C]

Mark,

In my current work environment, many people wear "readiness" badges.
I don't have one.
So, by definition, I'm not ready, and can't answer why I would be!

Peter

[kolechovski]

Well, actually, I'm not sure. I just remember once seeing the needle on the amp meter going to the left, and it went well into the red. I can't remember if brakes were in use or not.

[kolechovski]

Junction...here's a hint:

http://www.imagedump.com/index.cgi?pick=get&tp=178235

[M636C]

QUOTE: Originally posted by Junctionfan

I haven't asked this at least but what does the automatic brake do and what are the positions? I see things like SV and RL on the thing and don't know what they all do or stand for.

The mysteries of the Westinghouse system are generally beyond me!

But in the interests of continued good relations with Canada, here we go:

The "Automatic" brake is the air brake that applies the brakes on the train, as opposed to the "Independent" brake that applies the brakes only on the locomotive (or group of locomotives).

The brake is called "Automatic" because if the train breaks, or the pressure in the brake line is released, the brakes apply automatically. This is the opposite of the way the very early systems (or "Direct") air brakes worked. The change was made for safety purposes so that if a train broke a coupling, it would stop with brakes applied on both sections.

This means that the system is pretty complex and relatively slow acting compared to direct air brakes. The key feature is the "triple valve" that allows the single air pipe to provide:

a the signal to apply the brakes
b the signal to release the brakes
c to charge (raise the pressure in) the air reservoirs on each car

When a train breaks, or an air brake "application" is made, the pressure is "reduced" in the train line, and the difference between the pressure in the line and that in the air reservoirs determines the amount of braking you get.

I expect SV stands for "service" and this is a standard type of brake application, as opposed to an "emergency" application that drains the train line and allows all the pressure in the reservoirs to apply on the brake cylinders.

I also assume that RL is "release", and in this position, the pressure in the reservoirs is removed from the cylinders by sending a signal down the line. On a big train you can hear the sound of the air going down the line, in some cases. The system then recharges the brake reservoirs for the next application.

A problem is that if you are on a steep grade and make successive applications close together, you can run out of air pressure in the reservoirs. That is why you also have dynamic brakes, and the "independent" (locomotive only) brake which can be used instead of the "automatic" to conserve the air pressure in the train.

If this seems meaningless, I'll try again.

Peter

[M636C]

QUOTE: Originally posted by kolechovski

Well, actually, I'm not sure. I just remember once seeing the needle on the amp meter going to the left, and it went well into the red. I can't remember if brakes were in use or not.

My first answer was a bit flippant, but it sounds as though you have seen motors acting as generators.

To return to first principles, a DC machine can act either as a generator or a motor. This is fairly obvious in a locomotive fitted with dynamic brakes. Normally, you provide power to the motor and it turns and does work, or you apply power to the field and it turns by outside forces and acts as a generator.

But in fact, if a motor is turning faster than the voltage applied to it wants it to turn (the speed of a DC motor is controlled by the voltage across it), the "Back EMF", the voltage generated by the motor internally will exceed the voltage from the generator and will start driving the generator as a motor (since it isn't connected to the dynamic brake grids). This will show up as "negative amps". It is most likely to occur when running down grade with the train pushing the locomotive, possibly through a short dip where application of dynamic brake would not be required.

Peter

(the system is slowing down here, I'll be back later!)

[Anonymous]

QUOTE: Originally posted by M.W. Hemphill

Welcome to the four-star time-wasting club!

Here's your question:

Are you ready?

Why?

FOFLMAO...

LC

[locomutt]

QUOTE: Originally posted by M636C

Guys,

I'm worried about how much time I've wasted making postings on this Forum (mainly) and I've realised that they have generally been technical reponses to locomotive questions.

So here is an invitation to ask any questions you haven't asked yet!

Peter

Well Peter, [#welcome] to the Four Star Club!!!![:D]
I doubt that you have wasted any time in posting. I for
one am very interested in what you say. Now understanding
the technical stuff is another story.[:)]

Okay I'll bite;"How many locomotives;does it take to screw in
a light bulb" or does that go to another "union" to do[?]

[Anonymous]

QUOTE: Originally posted by M636C

Guys,

I'm worried about how much time I've wasted making postings on this Forum (mainly) and I've realised that they have generally been technical reponses to locomotive questions.

So here is an invitation to ask any questions you haven't asked yet!

Peter

Congratulations...

LC

[vsmith]

QUOTE: Originally posted by dharmon




Okay, what's the airspeed of a unladen swallow?


Dan

Is that an African swallow or a European Swallow?

[dharmon]

QUOTE: Originally posted by vsmith

QUOTE: Originally posted by dharmon




Okay, what's the airspeed of a unladen swallow?


Dan

Is that an African swallow or a European Swallow?

Shouldn't matter....they're both export variants..

[M636C]

QUOTE: Originally posted by dharmon

QUOTE: Originally posted by M636C

Mark

In my current work environment, many people wear "readiness" badges.
I don't have one.
So, by definition, I'm not ready, and can't answer why I would be!

Peter

HEYYYYYY .....I resemble that remark....


Okay, what's the airspeed of a laden swallow?

Congrats Peter...1000 posts and 99.9% of them on topic....

Dan

Dan,

Thanks, but I must ask, laden with....?

At this time of year, we have a swarm of big moths (called "Bogong" moths) that fly to the southern mountains to avoid the heat. They live on nectar and are quite sweet (I'm told) and are regarded as dessert by the local birds. The speed (and manouvrability) of some of these birds at low level, after a moth, is quite impressive. Say 50mph(?).

Peter

[locomutt]

QUOTE: Originally posted by M636C

QUOTE: Originally posted by dharmon

QUOTE: Originally posted by M636C

QUOTE: Originally posted by M.W. Hemphill

Welcome to the four-star time-wasting club!

Here's your question:

Are you ready?

Why?

In my current work environment, many people wear "readiness" badges.
I don't have one.
So, by definition, I'm not ready, and can't answer why I would be!

Peter

HEYYYYYY .....I resemble that remark....


Okay, what's the airspeed of a laden swallow?

Congrats Peter...1000 posts and 99.9% of them on topic....

Dan

Dan,

Thanks, but I must ask, laden with....?

At this time of year, we have a swarm of big moths (called "Bogong" moths) that fly to the southern mountains to avoid the heat. They live on nectar and are quite sweet (I'm told) and are regarded as dessert by the local birds. The speed (and manouvrability) of some of these birds at low level, after a moth, is quite impressive. Say 50mph(?).

Peter

Laden with what[?] surely not BIN[:D][}:)]

[dharmon]

QUOTE: Originally posted by M636C

Dan,

Thanks, but I must ask, laden with....?

At this time of year, we have a swarm of big moths (called "Bogong" moths) that fly to the southern mountains to avoid the heat. They live on nectar and are quite sweet (I'm told) and are regarded as dessert by the local birds. The speed (and manouvrability) of some of these birds at low level, after a moth, is quite impressive. Say 50mph(?).

Peter

Two AIM-7M (training CATMs) on the wing tips and a centerline tank.

Bogong.......is that the sound they make hitting the car when you drive through a swarm of them? [:)]

[locomutt]

QUOTE: Originally posted by dharmon

QUOTE: Originally posted by M636C

Dan,

Thanks, but I must ask, laden with....?

At this time of year, we have a swarm of big moths (called "Bogong" moths) that fly to the southern mountains to avoid the heat. They live on nectar and are quite sweet (I'm told) and are regarded as dessert by the local birds. The speed (and manouvrability) of some of these birds at low level, after a moth, is quite impressive. Say 50mph(?).

Peter

Two AIM-7M (training CATMs) on the wing tips and a centerline tank.

Bogong.......is that the sound they make hitting the car when you drive through a swarm of them? [:)]

(dweedle.........dweedle...........dweedle........dweedle...........!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!)[:D][}:)]

[M636C]

QUOTE: Originally posted by vsmith

OK how many locomotives does it take to screw in a lightbulb?

Congrates on the four star promotion!
[bday][bday][bday][bday]

In 1978-79, the Victorian Railways purchased ten GT26C 3000HP wide nose hood units known as class C, numbers 501 to 510. These were pretty impressive units at the time, but although they had steps at the front, there was no platform across the front (as built). The headlight bulbs were only accessible externally. So to change the front headlight bulb of a VR C class, the answer is "two locomotives are required to change a light bulb", any other unit with a platform backed right up to the coupler to give the electrician somewhere to stand. Later they just added a narrow platform on the nose.

Peter

[kolechovski]

Junction...I just read another forum...and I see exactly why you asked this question...so, how do you like the Trainmaster Demo so far? I think you could buy a package deal of it and Train Dispatcher 3 for around $50-60 back when they first came out. these days, if I could buy both for $20 or less, I'll gladly do it. Anyway, to help you with your train movements...M636C already gave many details, so basically, when you want to start releasing the brakes, choose RL. I can't remember what H is for, so you can try that and see what happens. Set it to LP when you want it to maintain whatever amount it's at. Use SV to start engaging the train's brakes. And if necessary, use the EMG (emergency) for any nasty situations you encounter. I think if you collect a few overspeed violations, or go too fast at once, the game forces your train into Emg anyways, although there may be a way to disable that auto-emg if it has that option. It's been a year since I've had the luxury of playing that game, so I don't remember much about it. If you're as screwey as me, and like playing around, I think if you press "V" on your keyboard, it takes you into a feature where you can explore the track forward and backward...check the documentation for details. Have fun, Trainmaster!

[M636C]

QUOTE: Originally posted by dharmon

QUOTE: Originally posted by M636C

Dan,

Thanks, but I must ask, laden with....?

At this time of year, we have a swarm of big moths (called "Bogong" moths) that fly to the southern mountains to avoid the heat. They live on nectar and are quite sweet (I'm told) and are regarded as dessert by the local birds. The speed (and manouvrability) of some of these birds at low level, after a moth, is quite impressive. Say 50mph(?).

Peter

Two AIM-7M (training CATMs) on the wing tips and a centerline tank.

Bogong.......is that the sound they make hitting the car when you drive through a swarm of them? [:)]

Dan,

"Bogong" is the name of a high plateau in Northern Victoria where the moths travel to in summer, passing through Canberra (and I mean through, they crawl under doors and hide in crevices) on the way.

Are you sure you mean AIM-7M on the wingtips? I've never seen radar guided Sparrows on the wing tips. Our F/A-18s carry AIM-9L Sidewinders on the wingtips, and Sparrows partly recessed on the intakes. We've got ASRAAMs now, with a better off boresight performance (ever since the Malaysians creamed us in an exercise with their MIG-29s!)

Peter

[Randy Stahl]

Why do tornadoes always hit locomotives that are parked next to trailer courts?
Randy

[ajmiller]

QUOTE: Originally posted by M636C
Dan,

Thanks, but I must ask, laden with....?

At this time of year, we have a swarm of big moths (called "Bogong" moths) that fly to the southern mountains to avoid the heat. They live on nectar and are quite sweet (I'm told) and are regarded as dessert by the local birds. The speed (and manouvrability) of some of these birds at low level, after a moth, is quite impressive. Say 50mph(?).

Peter

Laden with coconuts!
It could grip them by the husk!

[M636C]

QUOTE: Originally posted by Randy Stahl

Why do tornadoes always hit locomotives that are parked next to trailer courts?
Randy

Because, over many years, tornadoes have learnt that locomotives on their own tend to ignore high winds, so hitting it with a mobile (very mobile) home or two draws its attention.

Peter

[Junctionfan]

The autobrake has 5 settings. From left to right, RL, H, LP, SV and EMG (last one is in red writing). I don't know what the H does or the LP. I also have know idea what the independent brake is for but it always seems to stay on the left and can't move it expect to the middle where it sometimes goes back to the left on its own.

[M636C]

QUOTE: Originally posted by talbanese

Is there a limit to how many locomotives can be MU'ed? Do they need to be somewhat similar in performance and setup?

Congrats on the 4th star.

Tom,

Nearly missed this one!

One of the limitations relates to how MU is set up on the locomotive. On Alco export units, the lead locomotive was the only one providing the MU control power, and with voltage drop in the connectors it was felt that the practical limit was four units. With EMD units, each unit provided its own control power and it was quite possible to run more than twelve locomotives in multiple, since the voltage drop problem was overcome by each unit only "driving" the next in line. I believe the Alcos were modified to the EMD arrangement.

On other threads recently, "power reduction" was discussed. For example, the minimum speed of a GP40-2 is much higher than that of an SD40-2 simply because the same power is split through four motors rather than six, resulting in greater currents, and hence a greater heating effect in the motors of the four motor unit. Thus the power of the GP40-2 is reduced to an amount that will allow it to run for the same period as the SD40-2 at any given speed, so that motor damage does not occur.

Similar problems would occur running an AC unit leading a DC unit, because the AC unit can run almost indefinitely without overheating the motors at some low speeds, while a DC unit would have strict time limits at some low speeds available to AC units.

It is good practice to have the least powerful locomotive lead an MU consist, since any instance of overloading would be directly visible to the crew.

I hope this answers the question.

Peter