I thought I would be smart so today I decided to re wire my early Athearn F-7 A and B units. I ran wires from the positive side of the trucks to the top of the motor where the copper is and I ran a wire from the negative side to the bottom copper piece that meets the chassy. Both locomotives run fine except now I cannot get them to go in the same direction. Can someone please tell me where I may have gone wrong? The Locomotives are DC with no DCC.
Kevin
Can't stop working on the railroad!
Kevin,
Usually, the right front truck,picks up the positive + side of DC voltage,,so you probably have your layout wired so that rail is negative,like A being + and B being -,,,If it's the F-7 that is the one,that does that ,you'll have to reverse the leads at the motor,,,,,if it is the B-unit try turning it 180 degrees and back on the track..
That's one very good reason why I use,N&S, rather than A&B when doing wiring...
Cheers,
Frank
Frank is correct. Reverse the two motor wires on the offending loco.
Rich
Alton Junction
I think just turning the B unit around would solve the problem no matter which way they are wired, since it is DC only.
-Bob
Life is what happens while you are making other plans!
farrellaa I think just turning the B unit around would solve the problem no matter which way they are wired, since it is DC only. -Bob
Right.
The South rail is negative, the north rail is positive, then the train will move West
Turn the locomotive around and they will still move West.
You should really forget about forward and reverse. . You have East and West. with (-) on your port (south) side and (+) on your starboard (north) side, the train will move forward... er WEST. This is a function of the tracks and if your engines do not comply with this, reverse the leads to the locomotive.On some locomotives, reversing the trucks can also cause this to happen.
On the Realroad, diesel locomotives have an "F" painted on the front of the locomotive. The cab will be arranged so that the engineer will sit on the right facing the "F". If he has his reverser in FWD, the train will go that way. The 1:1 locomotive does not get its power from the tracks and so it does not care which way it moves in relation to the tracks.
The "F" tells the crew on the ground which way the locomotive will move when they ask the engineer to move the train "Forward" or "Backward". If the conductor is standing right by the locomotive where the engineer can see him, he can simply point to which way he wants the train to go. If the conductor is on the radio near the back of the train, and he does not know which way the locomotive is pointed (well he *should* know, it *is* his train after all) the words "Pull" or "Push" should convey the meaning well enough, but just for the fun of it I will ask over on the Trains forum.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
RRaddict I thought I would be smart so today I decided to re wire my early Athearn F-7 A and B units. I ran wires from the positive side of the trucks to the top of the motor where the copper is and I ran a wire from the negative side to the bottom copper piece that meets the chassy. Both locomotives run fine except now I cannot get them to go in the same direction. Can someone please tell me where I may have gone wrong? The Locomotives are DC with no DCC. Kevin
While you may have them wired identical, I'm willing to bet the trucks in the B unit are reversed. Either reverse the wires to the motor, or swap the trucks end for end.
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
The simplest solution I believe is to turn the B-unit around. With DC this will allow it to run in the opposite direction. If you don't like that solution:
I think you will have to switch the trucks on the B-unit, end-for-end. Switching the wires to the motor is going to give you a dead short since the motor is electrically connected to the chassis.
Remember its your railroad
Allan
Track to the BRVRR Website: http://www.brvrr.com/
BRVRRThe simplest solution I believe is to turn the B-unit around. With DC this will allow it to run in the opposite direction.
No, as explained above it does not work that way. They will still continue to go in opposite directions.
With correctly wired DC locos, you can couple them to run in consist back to back or elephant style and they will both run in the same direction unless the wiring in one of the engines is incorrect.
Mark,
Thank You,,
I'm willing to bet,,,that the chassis on the B- unit is a A-unit chassis...So if it don't work by turning it around,,the wires will have to be reversed...
Back on the big railroad similar issues obtain.
Good One,,LION,,
I missed that, havn't been on that site in awhile..
Fellas who are suggesting simply picking up and turning the B unit end for end, remember that this is one of the advantages that DCC has over DC. If you take two identical DC diesels and run them, they'll both chase each other around the tracks assuming they have identical running qualities as well. If you lift one of them and put it down backwards and apply voltage, you'd expect them to move apart, but that's not correct. Both will still move in the VERY SAME DIRECTION as before. The reason is that while you have reversed the loco, and thus the motor turning direction, YOU HAVE ALSO REVERSED THE WAY IT FACES ON THE RAILS! It will still move forward, but in the NEW DIRECTION. Ergo, both still chasing each other. In DCC, you can make the decoder instruct the motor to actually reverse its direction of rotation, but you don't also pick up the loco and plunk it down facing the opposite way. So, reversing motor actually makes that loco reverse.
If you want your DC B unit to chase its partner, you don't lift it up and swap ends, you reverse the trucks or swap the feeds to the motor terminals to force the motor to reverse ITSELF.
Crandell
And it is a lot easier to reverse the leads at the motor,than turning the trucks around...Period..
zstripe And it is a lot easier to reverse the leads at the motor,than turning the trucks around...Period.. Cheers, Frank
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Randy,,
I totally agree,,,,,,,as with,when all else fails,,read the instructions,,,,or read the original post..LOL..
Boy This Is Fun!?!
selector Fellas who are suggesting simply picking up and turning the B unit end for end, remember that this is one of the advantages that DCC has over DC. If you take two identical DC diesels and run them, they'll both chase each other around the tracks assuming they have identical running qualities as well. If you lift one of them and put it down backwards and apply voltage, you'd expect them to move apart, but that's not correct. Both will still move in the VERY SAME DIRECTION as before. The reason is that while you have reversed the loco, and thus the motor turning direction, YOU HAVE ALSO REVERSED THE WAY IT FACES ON THE RAILS! It will still move forward, but in the NEW DIRECTION. Ergo, both still chasing each other. In DCC, you can make the decoder instruct the motor to actually reverse its direction of rotation, but you don't also pick up the loco and plunk it down facing the opposite way. So, reversing motor actually makes that loco reverse. If you want your DC B unit to chase its partner, you don't lift it up and swap ends, you reverse the trucks or swap the feeds to the motor terminals to force the motor to reverse ITSELF. Crandell
Interesting that you see this as an advantage to DCC? Personally, as a modeler of the early diesel era, with lots of ABBA setups, I find all that consisting and direction changing with DCC to be one of the things that kept me out of DCC.
B units have a front and a back, and in DCC they run forward when you tell them forward, no matter how they are oriented to an A unit. Same with A units in ABA consists. So you have to change all that stuff around in the decoder - THAN when you want to uncouple them and use them DIFFERENTLY you have to change it back, or change it again for the new setup.
BUT, in DC, all my FA's run just fine together, they all go the same direction no matter what, they all MU just fine. Virtually all of my Proto2000 diesels can MU with each other, regardless of type - FA's, GP's, BL2's, etc, etc. And even mixed brands of F units like Genesis and Intermountain - all without the magic of DCC - imagine that. Not to mention all the steam locos of different brands I double and triple head.
As I have explained on here before, all this speed matching stuff is over blown. I run all sorts of different brands and types of locos together on DC with no problems.
To all the repondants who suggested just turning the B unit around - I would politely suggest you actually learn something about electricity before you attempt to answer a question about it, or, just stick to you "plug and play" DCC.
Sheldon
Contrary to what you've been told about DCC, you do not have to manually change any CV's in a decoder to mu them together or change direction. Yes, CV's are changed, but they are changed automatically during the MU set-up, and deleted when the engine is taken out of the consist.
To add an engine to a consist, you select the engine number, set the desired direction and you are off and running.
Say you have two GP40's and want to run them both facing the same direction .... no problem with DC, right ? But now you want to run them facing opposite directions to each other. In DCC, it's a matter of a couple key strokes - in DC, you have to rewire the motor to do this.
Which is easier now ?
Mark R. Contrary to what you've been told about DCC, you do not have to manually change any CV's in a decoder to mu them together or change direction. Yes, CV's are changed, but they are changed automatically during the MU set-up, and deleted when the engine is taken out of the consist. To add an engine to a consist, you select the engine number, set the desired direction and you are off and running. Say you have two GP40's and want to run them both facing the same direction .... no problem with DC, right ? But now you want to run them facing opposite directions to each other. In DCC, it's a matter of a couple key strokes - in DC, you have to rewire the motor to do this. Which is easier now ? Mark.
Mark, you are wrong. If I set two GP40's on a DC layout, they both run in the same direction, lets call it east or west, without regard to front or back.
Again learn something about DC and electricity before you talk about things you don't know.
To put it another way - you are standing in front of a length of DC powered track - you place a loco on that track, you turn up the power. The locos moves to the left. You do not touch the reverse swich on the power pack, you pick up the loco, you turn it around to face the other way, you turn on the power - GUESS WHAT? it still moves to the left.
I know how consisting works with DCC, but you still have to do it, and there are several methods, with DC you just put them on the track and go.
Respectfully, you need to go back through this thread and read what the LION and others explained, or just stay in your plug and play world where you don't know why things happen.
Mark R. ... But now you want to run them facing opposite directions to each other. In DCC, it's a matter of a couple key strokes - in DC, you have to rewire the motor to do this. Which is easier now ? Mark.
... But now you want to run them facing opposite directions to each other. In DCC, it's a matter of a couple key strokes - in DC, you have to rewire the motor to do this.
Mark, you don't have to rewire an engine you want tor run facing the other way in DC. You just have to pick up the locomotive and turn it around, and replace it on the tracks. When you dial in power, both locos will still chase each other...as I explained in my post above.
Suppose you have two F7 A units. They are tail to tail. You dial in your DC voltage and they'll both move in concert as the intended A-A unit. Then, you decide to switch the rear A unit so that they are like elephants, nose to tail. When you crank up the voltage again after they are coupled, they won't fight each other trying to move apart. They'll still move as the same A-A unit, except now nose to tail. The reason is that by lifting the rear A unit and swapping ends, you have also reoriented the direction of motor rotation with respect to the same track polarity as before. If the motor is now reversed in rotation relative to the same track, it moves the train in the reverse direction to before, except that its now the nose, and not the tail. So, the two A-A's still move as one unit in the very same direction.
ATLANTIC CENTRAL Mark R. Contrary to what you've been told about DCC, you do not have to manually change any CV's in a decoder to mu them together or change direction. Yes, CV's are changed, but they are changed automatically during the MU set-up, and deleted when the engine is taken out of the consist. To add an engine to a consist, you select the engine number, set the desired direction and you are off and running. Say you have two GP40's and want to run them both facing the same direction .... no problem with DC, right ? But now you want to run them facing opposite directions to each other. In DCC, it's a matter of a couple key strokes - in DC, you have to rewire the motor to do this. Which is easier now ? Mark. Mark, you are wrong. If I set two GP40's on a DC layout, they both run in the same direction, lets call it east or west, without regard to front or back. Again learn something about DC and electricity before you talk about things you don't know. To put it another way - you are standing in front of a length of DC powered track - you place a loco on that track, you turn up the power. The locos moves to the left. You do not touch the reverse swich on the power pack, you pick up the loco, you turn it around to face the other way, you turn on the power - GUESS WHAT? it still moves to the left. I know how consisting works with DCC, but you still have to do it, and there are several methods, with DC you just put them on the track and go. Respectfully, you need to go back through this thread and read what the LION and others explained, or just stay in your plug and play world where you don't know why things happen. Sheldon
Ahahaha .... It's been so many years since I actually ran anything on DC, I had to go try it again ! As far as "knowing" something about DC and electricity - I've probably forgotten more than you know. ;-)
Mark R. ATLANTIC CENTRAL Mark R. Contrary to what you've been told about DCC, you do not have to manually change any CV's in a decoder to mu them together or change direction. Yes, CV's are changed, but they are changed automatically during the MU set-up, and deleted when the engine is taken out of the consist. To add an engine to a consist, you select the engine number, set the desired direction and you are off and running. Say you have two GP40's and want to run them both facing the same direction .... no problem with DC, right ? But now you want to run them facing opposite directions to each other. In DCC, it's a matter of a couple key strokes - in DC, you have to rewire the motor to do this. Which is easier now ? Mark. Mark, you are wrong. If I set two GP40's on a DC layout, they both run in the same direction, lets call it east or west, without regard to front or back. Again learn something about DC and electricity before you talk about things you don't know. To put it another way - you are standing in front of a length of DC powered track - you place a loco on that track, you turn up the power. The locos moves to the left. You do not touch the reverse swich on the power pack, you pick up the loco, you turn it around to face the other way, you turn on the power - GUESS WHAT? it still moves to the left. I know how consisting works with DCC, but you still have to do it, and there are several methods, with DC you just put them on the track and go. Respectfully, you need to go back through this thread and read what the LION and others explained, or just stay in your plug and play world where you don't know why things happen. Sheldon Ahahaha .... It's been so many years since I actually ran anything on DC, I had to go try it again ! As far as "knowing" something about DC and electricity - I've probably forgotten more than you know. ;-) Mark.
Don't bet too much on that. And don't think for one minute that I don't use DCC because I'm "imtimidated" by it.
I don't use it because I know enough to build my own system that better meets my needs - CTC, signaling, truely working interlockings, radio throttles, etc.
And, I know enough about DCC to know I don't need or want it. I have used it quite regularly on the layouts of a number of friends, and even designed and helped wire some of those layouts.
I was designing complex relay control systems in the 70's, and converting them to PLC's in the 80's.
But the topic of this thread is something every 12 year old with a train set learned when I was that age.
So I find it amazing the number of people who got it wrong.
If all the computers stopped tomorrow, is there anyone left who could build one from scratch?
selectorMark, you don't have to rewire an engine you want tor run facing the other way in DC. You just have to pick up the locomotive and turn it around, and replace it on the tracks. When you dial in power, both locos will still chase each other...as I explained in my post above.
On AC systems, the locomotives would run in the direction they were facing.
Not so on DC systems. The properly wired locomotive will move forward when it gets (-) voltage on the left and (+) voltage on the right. END OF STORY!
If they do not do this, they are wired wrong (or in the case of Atheran, the trucks are reversed fore and aft)
On DCC an improperly wired locomotive will NOT operate in the direction that you expect it to run.
BroadwayLionNot so on DC systems. The properly wired locomotive will move forward when it gets (-) voltage on the left and (+) voltage on the right. END OF STORY!
Sigh! In an effort to make something clear, we now have what I consider a misleading statement. Two properly wired locomotives will both run in the same direction regardless of which way their "front" is facing. In the case of an A-A set coupled together back to back, if the lead unit is moving forward the trailing unit is moving backward in the same direction. Now if I remove the lead unit and make no polarity changes and operate the trailing unit, it will appear to be running backwards (in relation to the loco cab) even though it is running the same way it was before. This does not mean that it is improperly wired.
maxman BroadwayLionNot so on DC systems. The properly wired locomotive will move forward when it gets (-) voltage on the left and (+) voltage on the right. END OF STORY! Sigh! In an effort to make something clear, we now have what I consider a misleading statement. Two properly wired locomotives will both run in the same direction regardless of which way their "front" is facing. In the case of an A-A set coupled together back to back, if the lead unit is moving forward the trailing unit is moving backward in the same direction. Now if I remove the lead unit and make no polarity changes and operate the trailing unit, it will appear to be running backwards (in relation to the loco cab) even though it is running the same way it was before. This does not mean that it is improperly wired.
You can consider it misleading, but it is correct. As per NMRA S-9 which says:
"A. Direction control by polarity reversing shall be provided. Positive potential applied to the right hand rail shall produce forward motion. (3)"
http://www.nmra.org/standards/sandrp/s-9.html
In a back to back A-A set up, the "rear loco" does not have postive potential on the right hand rail relative to the loco cab - so the loco runs in reverse. The "front" loco does have positive potential to the right hand rail relative to the cab, so it run forward.
Once again, the reason for the Standard is to avoid the problem the OP had in the first place. Understanding these basics goes a long way in advancing our skills and and talents in this hobby.
ATLANTIC CENTRAL maxman BroadwayLionNot so on DC systems. The properly wired locomotive will move forward when it gets (-) voltage on the left and (+) voltage on the right. END OF STORY! Sigh! In an effort to make something clear, we now have what I consider a misleading statement. Two properly wired locomotives will both run in the same direction regardless of which way their "front" is facing. In the case of an A-A set coupled together back to back, if the lead unit is moving forward the trailing unit is moving backward in the same direction. Now if I remove the lead unit and make no polarity changes and operate the trailing unit, it will appear to be running backwards (in relation to the loco cab) even though it is running the same way it was before. This does not mean that it is improperly wired. You can consider it misleading, but it is correct. As per NMRA S-9 which says: "A. Direction control by polarity reversing shall be provided. Positive potential applied to the right hand rail shall produce forward motion. (3)" http://www.nmra.org/standards/sandrp/s-9.html In a back to back A-A set up, the "rear loco" does not have postive potential on the right hand rail relative to the loco cab - so the loco runs in reverse. The "front" loco does have positive potential to the right hand rail relative to the cab, so it run forward. Once again, the reason for the Standard is to avoid the problem the OP had in the first place. Understanding these basics goes a long way in advancing our skills and and talents in this hobby. Sheldon
However, what hasn't been reinforced is that the polarity to the rails must be reversed if you want the two A units to run in opposite directions, and that's critical.
Suppose:
A. You have a single DC loco...pick your loco...and have a 'normally wired' DC layout. You place your DC loco on the rails and apply power via your DC power pack. The loco moves...pick a direction. It doesn't matter....pick a direction.
B. Suppose you don't change a thing, but you add a second loco, identical in every respect, to the 'right of'' the first loco. Again, you apply power. What will happen? The pair, coupled or not as you placed them, will move in the same direction as in A above.
C. You couple the two locos, and everything else stays the same. You apply power. What will happen? They'll both move in the same direction, but this time as an "MU'd" unit for all practical purposes. Kewl.
D. You suppose that if you decouple the two 'MU'd' locos and turn one of them end-for-end, and recouple them, they'll enter a tug o' war and want to pull each other down the rails. Nothing electrical has changed, remember. What will happen? They won't tug on each other at all! They'll still move like the same MU'd unit as before. The logic has been explained....turnng the motor means you concurrently turn the direction of rotation relative to the unchanging polarity of the very same rails, and you STILL get two locos chasing one another. !!!
You won't even see a difference between the two if you change the polarity to the rails. Let's suppose you do that...what will happen? BOTH engines will reverse their direction of travel, per C above. Meaning, they'll both move in the opposite direction as before.
If this is mind bending, think of the direction of rotation of the armature in the motor. The armature is the rotating mass at the core of our DC motors. It depends strictly on the polarity of the rails. If it rotates around its axis one way with a certain orientation of polarity, won't it go the opposite way if YOU reverse the polarity with your power pack? Well, of course it will. If you don't reverse the polariy, but you pick up the loco and reverse it relative to the lead A unit, what willl happen? The end-swap of the loco will negate the reversal of the motor rotation caused by turning the polarity relative to the motor when you picked it up and swapped ends. If you negate a function, it must leave things as they are....and that means the two DC units still move in the very same direction as before.
So, how does DCC alter/change/improve things? It allows a single locomotive to move in either direction, provided you tell the decoder to make it do so. It allows an MU'd set to do so, provided you tell 'them' to do so...via their composite address (which the decoders are programmed to abide by when you MU them). And because the polarity to the track is irrelevant in DCC, because it's actually an AC current, the decoder/brains will perform the function you set for them.
This next statement is definitive as a difference between DCC and DC:
If you want 'normally' wired DC locomotives to move away from each other relative to the direction of travel of a given (pick one) locomotive, you MUST...must...have a gap in the rails between them some place, and have the power pack supplying a reversed polarity via a switch or selector.
The selector in DC is obviated by the decoder if you wish to perform the same function in DCC.
The selector in DC is obviated by the decoder if you wish to perform the same function in DCC
Crandell,
What does that have to do with any thing being diescussed here? The OP is not using DCC, and most of the brainless responses came from those who do.
I want gaps between any two locos going in oposite directions, in fact I want gaps between any two locos operated by different operators - because, like the real railroads, I don't want any crashes - but that's just me.
In fact, I use staggered gaps, seperate power supplies,and no common rail so that trains CANNOT over run their assigned power section and be picked up by someone elses throttle - more simple science from the 5th grade nobody understands - Are you smarter than a 5th grader?
This was a DC question, but somehow now you have made it into a DC vs DCC thread, like so many others before you with this "if you used DCC you would not have this problem" approach.
The OP did not ask for advice on how to control his layout, or how to run more than one consist at a time on the same track.
He simply wanted to know how to get the two locos to run the same direction like they did before he worked on them - and he got a bunch of incorrect info from all the DCC "experts" on here - nothing new.
Yes, I prefer to control the track and not the train - why? partly because I am not actually in the cab of the train, and partly because I like to be the dispatcher rather than the engineer, even when I run by myself, and partly because I can get more of the features I want for less money and work, and partly because I don't like any of the available user interfaces (throttles for those of you from Rio Linda) in DCC, and partly because I have no use for onboard sound that sounds as much like a locomoitve as a nine transistor radio from 1963.
Are you smarter than a 5th grader? - not if you don't know how a DC model train works.
Once again I will suggest that the title of this section of the forum is ELECTRONICS AND DCC, with AND being the key modifier - there were electronics in model trains LONG before DCC.
ATLANTIC CENTRAL .... If all the computers stopped tomorrow, is there anyone left who could build one from scratch? Sheldon
.... If all the computers stopped tomorrow, is there anyone left who could build one from scratch?
Personally, I would hope not.
Depends, the level of a modern PC with Windows, or a Mac? Not likely, the speeds are such that they absolutely need tightly controlled design of multi-layer circuit boards in order to function. Even an early PC compatible type machine could be fairly easily assembled from parts, they are also slow enough to not need super crticial interconnects between the chips.
A computer, that can run repetetive programs, and do calculationsamny times faster than the typical human brain? Absolutely could build something like that froma pile of parts, they run slow enough that point to point hand wiring is plenty sufficient. In fact, one version of the CPU used in my very first computer I built some 36 years ago was available as silcon on sapphire, radiation hardened and space rated, so it may even survive a nuclear event and still function. Even an early PC compatible type machine could be fairly easily assembled from parts, they are also slow enough to not need super crticial interconnects between the chips.
Getting bombed back to the stoen age is a little far fetched - it would assume that every single person with ANY tech skills at all - precision machining, modern farming, basic electronics, etc - is wiped out.
--Randy