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

[Modelcar]

...Congrats Peter...now you have 4 golden stars to install on your locomotive....!

[edblysard]

Well, tie me kangaroo down, boys.....

Please, respond with as much technical stuff as you can, after all, thats why people ask you guys those questions, because you have the knowledge, and they need it...

Never boring, always a great source.

Ed

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

[Anonymous]

QUOTE: Originally posted by Randy Stahl

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

FOFLMAO...

They never hit the ones parked near the mansion...oops...hey there's no track near the mansion?? Go figger...LOL...

LC

[Anonymous]

Peter-

Technical question.

How many cylinders does an RS-18u have in its Alco/MLW 251 Engine?

LC

[M636C]

QUOTE: Originally posted by 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 no idea what the independent brake is for but it always seems to stay on the left and can't move it except to the middle where it sometimes goes back to the left on its own.

OK, I've said I'm not an expert and right now I can't think what "H" stands for.
LP stands for "LAP". I think I've been told that having made a "Service" (SV) application, the handle is normally brought back to "Lap" ready to make another application. Moving back to "lap" does not release the application already made.

Now thinking further about it, it is possible that H stands for "Hold". If my thought is correct, in that position the handle is also not going to change the brake setting, but is closer to the "Release" position allowing an easy movement to release the brakes.

One of the positions L or H might allow recharging of the reservoirs. That has to be possible at some setting.

EMG means "Emergency" and will apply maximum braking on all vehicles. You really don't want to do that on a real train unless you have to, because not all vehicles brake evenly, and an emergency application put a lot of stress on the couplers, and can lock up wheels causing them to skid on the rail, some times picking up some steel from the rail or getting a small 'flat' on the wheel. That's why it is marked in red.

The names and positions of the handle relate to the way the air brake valve is built and what it does to the air, rather than being positions for a given effect on the brakes. For example, making an emergency application was sometimes called "big-holing" because to make an emergency application, the brake handle opens the biggest "hole" to let air out of the train pipe. "Service" has a smaller hole, so the application is slower, but if you leave the handle in SV, eventually all the air will come out and the brakes will be on just as hard as if you made an "Emergency" reduction.

So the amount of braking depends both on the position you use, and the time you spend making the application.

The independent brake isn't as complex, because it des not affect the whole train, and does not rely on pressure reduction in the train pipe. You can apply it and more particularly, release it more quickly. It has a different effect on the train, too. If you apply the independent brake at speed, all the braking occurs at the locomotive, and the train "Bunches up", with all the couplings compressed. If you apply the Automatic, the locomotive brakes aren't applied (except in "Emergency") and all the braking occurs in the train, stretching the train out.

If you were driving a passenger train, and wanted a smooth start, you would stop using the Automatic, leaving the train stretched out. Then you can start smoothly with no jerks as the couplings "take up" the strain.

If you have a very heavy freight and you don't want to load the locomotives right up, you could get a rolling start by stopping with the independent brake, "bunching" the couplings. Then as you start, you get the train moving one car at a time, reducing the initial load on the locomotives.

There must be people who know more about it than me, but that's my best effort.

Peter

[M636C]

QUOTE: Originally posted by Limitedclear

Peter-

Technical question.

How many cylinders does an RS-18u have in its Alco/MLW 251 Engine?

LC

To quote a famous British car racing commentator;

"Unless I'm very much mistaken..." Twelve cylinders

The only pre-Century series sixteen cylinder MLW was the demonstrator RSD-17 "Empress of Agincourt". That is, always assuming that the RS-18u still has a 251 engine. Some might have had Cat engines installed. Didn't BC Rail do something like that?

Peter

[dharmon]

QUOTE: Originally posted by 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

Very good catch on the 7 vs 9, I didn't realize I had made that mistake......I bow to your greatness.

29's are a heck of a plane, they make average pilots good, and in the hands of talent, they can be absolutly deadly.

[mloik]

QUOTE:
To quote a famous British car racing commentator;

"Unless I'm very much mistaken..."

Peter

Peter,

Is that Jackie Stewart to whom you are referring?

Michael

[miniwyo]

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?

I don't know..... AAAAHHHHHHHHHHHHH

[Anonymous]

QUOTE: Originally posted by M636C

QUOTE: Originally posted by Limitedclear

Peter-

Technical question.

How many cylinders does an RS-18u have in its Alco/MLW 251 Engine?

LC

To quote a famous British car racing commentator;

"Unless I'm very much mistaken..." Twelve cylinders

The only pre-Century series sixteen cylinder MLW was the demonstrator RSD-17 "Empress of Agincourt". That is, always assuming that the RS-18u still has a 251 engine. Some might have had Cat engines installed. Didn't BC Rail do something like that?

Peter

Very good...

LC

[M636C]

QUOTE: Originally posted by mloik

QUOTE:
To quote a famous British car racing commentator;

"Unless I'm very much mistaken..."

Peter

Peter,

Is that Jackie Stewart to whom you are referring?

Michael

Michael,

No, it was Murray Walker (just a commentator, never a driver)

I can recall his "Unless I am very much mistaken.....and I AM very much mistaken" on at least one occasion. There is a web page dedicated to the strange things he's said!

For some reason, I watched a lot of F1 broadcasts on Sunday nights when nothing else was worth watching.

Peter

[zardoz]

QUOTE: Originally posted by miniwyo

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?

I don't know..... AAAAHHHHHHHHHHHHH

Nice to know there are a few Monty Python fans out there!


And now for something completely different.....

[Mookie]

Peter: Here is a toughie. M636C?

Mook

[Paul Milenkovic]

Gee, with all the good-natured ribbing going on, I hope I am not ruled out of order for getting serious.

The F40Ps had their Diesel going a mile a minute to provide HEP (Hotel Electric Power I am told is correct -- they also have HEP on a cruise ship). I understand that none of the GE Genesis units, the DC P40 and P42s as well as the AC P32ACs have their main Diesel reved up like this, but none have a separate HEP Diesel. I read that the P32ACs use a variant of a "traction inverter" (i.e. a whole lot of electronics) to generate the HEP from the variable-speed main Diesel.

Question 1: what is the HEP scheme on the DC Genesis (P40/P42) -- they don't have the fancy traction inverter electronics?

Question 2: what is the fuel penalty for running the Diesel at full RPM and at part load? I saw a Web site that a Diesel at low-speed idle uses very little fuel compared to full throttle. What percent of full throttle fuel usage do you have when the Diesel is going full tilt but you are drawing very little load?

[SALfan]

QUOTE: Originally posted by Randy Stahl

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

DUHHH!!! You must have never lived down South - everybody down here KNOWS trailer parks are tornado magnets. (No offense, Randy - just couldn't resist pulling your chain.) Riddle: How is a Texas tornado like an Arkansas divorce? Answer: Somebody is "fixing to" (Southern for "about to") lose a trailer!

[M636C]

QUOTE: Originally posted by Mookie

Peter: Here is a toughie. M636C?

Mook

About thirty years ago, I was working for the Mt Newman Mining Company, initially in Perth, Western Australia and later in Port Hedland much further north in the same state. They had just taken delivery of the last M636 which they insisted be fitted with Alco Hi Ad trucks, rather than the MLW Dofasco design that came as standard. The MLW Dofasco is a good truck, but it was designed to reduce curve forces in sharp curves and to reduce track stresses. Mt Newman felt that since they had a seven year old railroad with no sharp curves all laid with 136lb rail, they'd stick with the Hi Ad. These units were numbers 5469 to 5495. Later the builder refused to build any more units with Hi Ads, so, reluctantly they bought 5496 to 5505 with MLW Dofasco trucks. So we had to think of a way of telling the locomotives apart. A friend pointed out that MLW built C630s with MLW Dofasco trucks were called C630M, so our units with Hi Ads had to be M636C. (Montreal design with Century series trucks). They have all gone now, but all but one (5495) were rebuilt from the frame up as GE Dash 8s (keeping the Alco Hi Ad trucks). All the MLW Dofasco fitted units were scrapped or donated for preservation.

Peter

[M636C]

QUOTE: Originally posted by Paul Milenkovic

Gee, with all the good-natured ribbing going on, I hope I am not ruled out of order for getting serious.

The F40Ps had their Diesel going a mile a minute to provide HEP (Hotel Electric Power I am told is correct -- they also have HEP on a cruise ship). I understand that none of the GE Genesis units, the DC P40 and P42s as well as the AC P32ACs have their main Diesel reved up like this, but none have a separate HEP Diesel. I read that the P32ACs use a variant of a "traction inverter" (i.e. a whole lot of electronics) to generate the HEP from the variable-speed main Diesel.

Question 1: what is the HEP scheme on the DC Genesis (P40/P42) -- they don't have the fancy traction inverter electronics?

Question 2: what is the fuel penalty for running the Diesel at full RPM and at part load? I saw a Web site that a Diesel at low-speed idle uses very little fuel compared to full throttle. What percent of full throttle fuel usage do you have when the Diesel is going full tilt but you are drawing very little load?

Paul,

No, it's my thread and I volunteered to answer questions!

In fact, the P40 and P42 use the same technology as the P32AC to convert the HEP power to constant frequency AC. The process is that the variable frequency (dependent on engine speed and hence throttle notch) power is converted to DC in a rectifier and then converted further to constant frequency AC in an inverter, generally called a "static frequency converter". In the P40 and P42, the converter can only produce 60Hz three phase power for the HEP supply. In the P32AC there are five identical converters that take all the locomotive power, and four of them produce variable frequency, variable voltage three phase AC to drive the traction motors and the fifth produces only the 60Hz HEP power. Since the five are identical, it doesn't matter which one produces HEP, so if one converter fails, the P32AC can run on three motors and still provide HEP power to the train. The equipment in the P40/P42 is simpler because it doesn't have to be able to produce the varying frequency required to drive the traction motors at different speeds.

I'm sorry, I don't know the fuel penalty for running the 645E3 at 900rpm continuously at low power. Strangely enough I can give you the figures for the GE LM2500 marine gas turbine at 3600rpm (but I won't because it is quite different physics involved). Running diesel engines at high speed and low power is bad for them. One of the stupid features of the M636 was the use of the main blower to cool the dynamic brakes, rather than the braking current driven fans on most EMD, GE (and yes most Alco) designs. The M636 had to be run in notch 8 when in dynamics, and the same engines deteriorated faster than they did in the C636. So the F40PH wore its own engine out more quickly, hence the Amtrak F40PHs wearing out faster than, say the Conrail, ex PC, ex NYC GP40s that seem to have been around forever. While the engine is running at 900 rpm in the F40PH, the small amount of fuel being used probably doesn't give the EMD turbo enough exhaust to run free, so you are driving the big centrifugal blower at full speed from the engine, and there is a lot of power used there, and since this is being driven, the turbocharger related fuel economy increase won't occur during "HEP Only" operation.
Somewhere in the back of my mind is a statement, probably from the MBTA, that the F40PH used 30% more fuel than their "FP10" units on the same duty. Certainly, MBTA bought the first F40PH units with separate HEP generator diesel engines, and have had MPI rebuild their "standard" F40PH units with separate HEP.

Peter

[AlcoRS11Nut]

Nice on the 4th star....but here is my question.....what is the diameter of a piston (or cylinder) of a EMD H-series prime-mover? The reason I asked this odd question is that my cousin and I were talking the other day and he said that it was a foot across. I don't know that just seems kinda large to me, even the H series. Is he right or it is bigger/smaller?

[M636C]

QUOTE: Originally posted by AlcoRS11Nut

Nice on the 4th star....but here is my question.....what is the diameter of a piston (or cylinder) of a EMD H-series prime-mover? The reason I asked this odd question is that my cousin and I were talking the other day and he said that it was a foot across. I don't know that just seems kinda large to me, even the H series. Is he right or it is bigger/smaller?

This is one of the really easy ones!

EMD changed their method of engine classification, because (I think) the new H engine was more than 1000 cubic inches per cylinder, and would require a four digit number rather than a three digit number. So the decision was made to describe four stroke engines by their diameter in millimetres, in the H engine case it is "265H", about 10.43 inches. The engine STROKE is close to one foot, however. The small four stroke engine built by Caterpillar is described as a "GM170" when fitted in a GP15D, for example. While on the subject of Cat, their next size engine, the 3600, used in the now modified MK5000, was 270mm cylinder diameter. So you had a step of 100mm cylinder diameter between engine models! The MK5000 units now use EMD 645F engines.

Peter

[jockellis]

I used to rent an apartment from a retired road foreman of engines in Waycross, GA who had kept the owners manual from a U-25 he had once operated. I hope you can help me but it said something about the electric motor running in different modes and in my memory they were series, series shunt, series-parallel and parallel shunt (or something like that) . Could you refresh my memory and tell me what all that mumbo jumbo means?
Jock Ellis

[oltmannd]

....that's two questions.....

[oltmannd]

QUOTE: Originally posted by jockellis

I used to rent an apartment from a retired road foreman of engines in Waycross, GA who had kept the owners manual from a U-25 he had once operated. I hope you can help me but it said something about the electric motor running in different modes and in my memory they were series, series shunt, series-parallel and parallel shunt (or something like that) . Could you refresh my memory and tell me what all that mumbo jumbo means?
Jock Ellis

It's the way GE kept the locomotive's performance on the 2500 HP curve throughout it's speed range. They had to do it because of current and voltage limitations of the main generator and traction motors.

In parallel, all 4 traction motors are connected to the main generator in parallel. As you go slower, the voltage goes down and the current goes up. Soon, it is too high for the main generator, so you reconnect the motors. You connect each pair of motors in series and then the two series pair in parallel to the main generator. This doubles the voltage but halves the current from straight parallel.

The shunting comes into play at the high voltage/high speed end. You weaken the field by shunting some of the field windings in the traction motor so that the voltage goes down and the current goes up a bit. This allows the locomotive to continue to produce full HP at high speeds.

Now, with traction alternators instead of generators and good, high voltage diodes to make DC from the AC, plus the advent of generator transition, a 4400 HP DC locomotive has no motor transition nor field shunting.

[Randy Stahl]

OK... This ones for real ! Can anyone provide me with a formula or method for calculating fuel usage on an EMD F-40
Randy

[oltmannd]

Randy-

You want the burn rate by notch? Should be almost exactly that of a GP40-2 in freight mode, which I can get you, if that's what you need....

[Randy Stahl]

QUOTE: Originally posted by oltmannd

Randy-

You want the burn rate by notch? Should be almost exactly that of a GP40-2 in freight mode, which I can get you, if that's what you need....

That will work !!!!
Randy

[Willy2]

Congratulations on four stars! [tup]

[M636C]

QUOTE: Originally posted by Randy Stahl

QUOTE: Originally posted by oltmannd

Randy-

You want the burn rate by notch? Should be almost exactly that of a GP40-2 in freight mode, which I can get you, if that's what you need....

That will work !!!!
Randy

But not if it is supplying HEP power to a passenger train, as outlined in my comments above, because the engine will be running at a constant 900 rpm even at idle, and will have a load of a couple of hundred kW on top of any "locomotive" functions.

Peter

[M636C]

QUOTE: Originally posted by oltmannd

QUOTE: Originally posted by jockellis

I used to rent an apartment from a retired road foreman of engines in Waycross, GA who had kept the owners manual from a U-25 he had once operated. I hope you can help me but it said something about the electric motor running in different modes and in my memory they were series, series shunt, series-parallel and parallel shunt (or something like that) . Could you refresh my memory and tell me what all that mumbo jumbo means?
Jock Ellis

It's the way GE kept the locomotive's performance on the 2500 HP curve throughout it's speed range. They had to do it because of current and voltage limitations of the main generator and traction motors.

In parallel, all 4 traction motors are connected to the main generator in parallel. As you go slower, the voltage goes down and the current goes up. Soon, it is too high for the main generator, so you reconnect the motors. You connect each pair of motors in series and then the two series pair in parallel to the main generator. This doubles the voltage but halves the current from straight parallel.

The shunting comes into play at the high voltage/high speed end. You weaken the field by shunting some of the field windings in the traction motor so that the voltage goes down and the current goes up a bit. This allows the locomotive to continue to produce full HP at high speeds.

Now, with traction alternators instead of generators and good, high voltage diodes to make DC from the AC, plus the advent of generator transition, a 4400 HP DC locomotive has no motor transition nor field shunting.

Since the manual refers to three connections,

These would be:

series = four motors in series
series parallel = two groups of two motors in series
parallel = all four motors in parallel (each taking full voltage)

These are "series-wound" motors, so all the armature current also passes through the field windings, generating a magnetic field (sometimes called "flux"). The motor speed is dependent on the voltage and the magnetic field. You can go faster by making the voltage higher, or the magnetic field smaller. The "resistance" of the motor to the current is the "back EMF" generated by the magnetic field. So when you can't raise the voltage to increase the speed, you can reduce the magnetic field by providing a "shunt" or diversion, that allows part of the current to bypass the field windings (and not generate "Back EMF") but still flow through the armature.

The field shunting or diversion, can be applied independent of the actual connection of the motors in series or parallel, but this will be determined by the control system which makes the connections.

It might actually be more complicated than it sounds.

I understand early U boats also had sixteen throttle notches, too, but only eight were used if in multiple with an Alco or EMD!

Peter

[Randy Stahl]

I'll take into consideration the HEP , I think the HEP is about 500 kw . I'll go ahead and consider how many gallons per horsepower , per hour. Or use the GP -40 chart and fiddle with the numbers.
Randy

[Sterling1]

QUOTE: Originally posted by M.W. Hemphill

Welcome to the four-star time-wasting club!

Here's your question:

Are you ready?

Why?

GRRR!!! teeth nashing . . . slogging at 2 somes still hauling out to the three some stars . . .