I bought a BLI 2-8-2 Mikado around 9 years ago.
I never did anything about it, but the connection rods jam and lock up on occasion. The most recent time that it happened, I called BLI about the problem. They will repair it for $65, but the original parts are no longer available, so they would use parts from the current line of Mikados and put my shell on top of the rehabbed chassis. Fair enough, but I am too cheap at this point to spend the $65.
To free up the connecting rods in the past, I have had to remove the plastic plate that holds the driver wheels and connecting rods in place and fiddle with the driver wheels.
This time, I decided to look more closely at the problem. If you look at the first photo, a shot from the side of the loco, the area inside the green circle was where I initially thought that the problem was occurring. The rods that slide on the top and bottom of that assembly had fallen off to the side of the assembly and locked up. However, over time, as it jam and lock up occurred, I noticed that the connect rod itself was bending, as seen in the area inside the red circle.
But, now, if you look at the second photo, a shot from the bottom of the loco,I have circled a third area in blue. That square bronze bearing doesn't stay in place with lateral movement of the wheels. The other three driver sets and their square bronze bearings hold into place on the first three driver wheel sets, but not on that rear set of driver wheels. Usually, this is not a problem, but in the event of a derailment, this excessive lateral movement causes the connecting rods to slip, jam, and lock up.
This doesn't happen often because derailments do not occur often except in the case of operator error. But, when it happens, the connecting rods jam up and lock. And, of course, the resulting bending of that connecting rod has weakened it.
I have checked with an NMRA gauge and the driver wheelsets are all in gauge. What I cannot figure out is why there is so much lateral movement in that fourth wheelset which I believe is at the heart of the problem. I am afraid that I do not fully understand how these square bearings interact with the wheelsets. Why do they not stay in place and why the excessive lateral movement of that set of driver wheels?
Any ideas? Anyone else have this problem?
Incidentally, in that second photo, the bottom view, the front of the loco is to the right.
Rich
Alton Junction
Hey, Rich,
I have a 2-3 yr old BLI mikado and have not had the problem, but I'll dive in a bit anyway. I may just need to reread your description (e.g., is it the main, connecting or eccentric rod that bends, and what is it hanging up on?) but am not clear on what is binding and locking up (what hits what first, or is that bronze bearing block sliding out of its slot?).
On my 2013 Athearn challenger, I had a problem where the eccentric rod could come around and hit one of the connecting or main rod nuts and it got bent. It turns out that is not uncommon on the Genesis 2013 challengers and 2014 big boys. I managed to bend the eccentric crank out a bit but bent the rod too much and managed break the rod. Consulting with Athearn's repair tech he sent a free replacement rod & crank and advised how to check the clearance, etc, so I got past that successfully. All this just to make the points of determining the interference issue exactly and if bending things that seem bendable, some of these parts have limited flexibility.
Perhaps more helpful to your situation, if the rear driver lateral movement is the real source of the problem, perhaps that movement can be limited. On my BLI mountain (not the current Paragon2 but the prior ones) it is my most finnicky regarding derailments, e.g., backing over a curved not entirely flat turnout the rear driver tries to climb over the rail. My LHS guy thought the springs might be changed to help this, but it did not. (I think it had non-stock springs as that release needed several adjustments, but he thought some NWSL springs might help, but it did not). Getting to my point, he made thing much better by doing two things. The first was reducing the rear (and front, I think) drivers lateral play by adding washer shims, some Kadee gray fiber washers with a slot cut out so the washer could simply be slipped onto the axle. (They are not so easy to get off). (Also, adding two per side made things worse). That reduced the problem. He then also adjusted the spring force on the trailing truck, which pretty much solved the remaining problem when backing.
Probably more info on my mountain than you need, but I was uncertain whether the interference binding point cause is clearly understood and/or whether simply reducing the driver later movement would help.
Maybe some of the above will be relevant to your situation or stimulate other ideas. If you want to inquire of my LHS guy, Mike, perhaps he can offer some insight on the specific BLI with a different perspective than the BLI folks, as he certainly had familiarity with the mountain version quirks. He is Mike at Dibbles Hobbies in San Antonio.
Paul
Modeling HO with a transition era UP bent
Rich,
I have a pair of BLI Mikes. If you look at the bottom cover plate, you will see a series of pins that hold the main driver bearings in place. The bearings have to be inside the pins on the cover plate to limit the side play of the drivers. this should solve the problem of the side rods binding. That said, it's a real bugger to get all of the bearing inside the pins at the same time. A good pair of magnifiers and a couple of small screwdrivers help. Hope that splves your problem.
PS
Paul, thanks for that reply. It was very helpful and got me thinking even more about the problem and its cause.
I am not sure at this point what is causing the connecting rods to bind and lock up the driver wheels. But from everything that I have studied about it when it happens, I am convinced that either the square bronze bearing is falling out of its housing or else it is the excessive lateral movement of the third set of driver wheels (perhaps caused by that bearing falling out of place).
I am not all that familiar with the names of the various connecting rods, but it is the outermost rod and it connects the second and third set of driver wheels (eccentric rod ?). If you look closely at that rod, inside the red circle, the rod is bent in the middle.
Your comments about adding a washer to the axle to restrict lateral movement is interesting. Would I need a wheel puller to remove the wheel in order to insert the washer?
You need to determine if the rear axle play is engineered into the unit or is caused by wear.
Jim
Part of the problem may be that the eccentric crank (the short, vertical part on the third driver in your first photo) is improperly positioned. Its bottom end in the photo should be pointing roughly to the mid-point of the counterweight on that wheel.You may have to remove the hex-headed screw which holds it in place in order to re-align things. Also, check for the same problem on the opposite side of the loco. The problem of the lock-up, though, sounds to me as if you have an out-of-quarter driver. It's not on the side of the loco showing, though, as all of the wheel counterweights are in roughly the same position relative to one another. Check the other side to see if their positions are similarly relative (they should all be in a different position from the side shown by about 90°).
Wayne
I concur with Wayne. Theres something not right about your eccentric crank in the side view photo. Put her in 'rods down' position and check both sides. Not that model locos conform to the real action of side rods, but they must work close to it to keep from binding or locking up. This should also help in checking if the drivers are correctly quartered.
Check too to see if (not likely but....) a driver isnt loose on the axle, giving it the ability to 'freewheel' against the rods. This would cause a lock up or bind. This is rare however it happens. I had once a loco (Rivarossi) with a split in a driver right at the axle housing. With the play that is inherent in model rods, this caused the wheel to move out of synch with the rest of the drivers. And ofcourse, a bind.
Douglas
doctorwayne Part of the problem may be that the eccentric crank (the short, vertical part on the third driver in your first photo) is improperly positioned. Its bottom end in the photo should be pointing roughly to the mid-point of the counterweight on that wheel.You may have to remove the hex-headed screw which holds it in place in order to re-align things. Also, check for the same problem on the opposite side of the loco. The problem of the lock-up, though, sounds to me as if you have an out-of-quarter driver. It's not on the side of the loco showing, though, as all of the wheel counterweights are in roughly the same position relative to one another. Check the other side to see if their positions are similarly relative (they should all be in a different position from the side shown by about 90°). Wayne
Do the position of the driver wheels and eccentric cranks look right?
I am wondering about something else. The first three sets of driver wheels are geared but the fourth set of driver wheels is not geared. So, is it supposed to have more lateral movement that the geared wheelsets?
The drivers seem to be quartered from the pics.
This is what I do in these situations: I remove the boiler and remove the motor. This allows me to (gently) roll the wheels freely to see what's going on. In 95% of the cases, I will locate the problem and fix it (could be a screw or a rod rubbing against something). Now in your case, you say that the bronze bearing is not staying put. Are you sure that the bottom cover is fastened properly? I had a bowser that gave me problems because of this. If the screws are not on tight, it would move around. As mentioned earlier, all the components need to fit in snuggly. Normally, these components should not move, but most locos of this size (with flanges) will have some play in the middle drivers to negotiate curves.
Let us know what happens.
I agree with Wayne and Douglas. Built quite a few Mantua & Bowser steamers, once learning how, they will roll without Motor on a sheet of glass. Some lateral movement is necessary on drivers.
Take Care!
Frank
Rich, some additional thoughts:
- on my BLI mike, I decided to lube it and when doing so, I managed to mess up the spring arrangement so something was out of whack and had to send it in for expert help
- some comments above talk about quartering problems. If I understand correctly, the loco runs smoothly when not derailing, so that sounds like ok quartering. If the binding occurs only when derailing due to misthrown turnout or track abnormalities, I'd guess the key problem(s) don't include quartering getting off, or it would just run funny (lopping). (how do you spell "loap-ing"?). I suggest figuring out what can cause it to derail consistently and then make it happen repeatedly and closely observe what happens first (e.g., rear driver moves lots laterally?), second (connecting rod mechanism binds?), third (binding distorts whole rods mechanism and eccentric rod hits and gets hung up on rod bolt and bends???), if at all possible. Oh, the split Kadee washer just slips onto the driver axle shaft between the bearing and wheel. It's easy to get on, but hard to grab to pull off as it requires real thin tweeers to grab the edge of it when on.
I still suggest talk with BLI some more or Mike at S.A. Dibbles Hobbies if he doesn't mind as he may have specific insight to this situation. I was impressed by how much Mike knew about the very slightly used (earlier version) BLI Mountain that I bought there. Apparently that run had some key problems such as poor driver bearing machining, driver springing being substandard (I my be remembering the spcifics wrong) and/or other things where most (as opposed to a few) of the run 's items needed significant work.
Oh, as I learned on my Athearn challenger issues, the main rod is the one that goes from the piston to the driven wheel, the "connecting" rods are the short ones that couple the 4 dirvers in unison, and the eccentric rod is the small one that the eccentric crank (on one of the driver bolts) moves in and out of the cylinder system to move the valve system in the small cylinder atop the piston clyinder).
I'm grabbing at straws a bit but trying to add some perspective. Do let us know if you figure this out.
I am going to have to examine the driver wheels and connecting rods much more closely the next time that they lock up.
Normally, the loco runs just fine, even at top speeds, with no jamming or lockups whatsoever. It is only when a derailment occurs, and that is not often - - only through operator error on a turnout.
If I turn the loco upside down and move the driver wheels back and forth with my fingers, there is some lateral movement, but not enough to touch the plastic cover plate. This is true for the first three sets of driver wheels. However, the fourth set shows much more lateral movement, touching the plastic cover plate.
It is my feeling, right or wrong, that when the loco derails, the lateral movement of this fourth wheelset reaches the plastic cover plate, whereas when the loco is on the rails, there is little lateral movement. This excessive lateral movement of the fourth wheelset causes the eccentric rod to jam and bend, knocking other connecting rods out of position, locking up the entire set of 8 driver wheels.
Incidentally, the three screws that hold down the plastic cover plate are completely screwed in, securely holding down the cover plate over the driver wheels and bearings. I still cannot help but wonder if the square bronze bearing on the left side of the fourth driver wheelset is not machined properly, causing this whole series of catastrophic events.
If I can figure this out, I will get back to everyone.
Rich, the drivers appear to be in-quarter on both sides, but that left side eccentric crank needs adjusting. In its current position, the motion through the connecting linkage means that the movement imparted to the valve stem occurs at the wrong time and may actually be causing the free end of that valve stem to drop out of the valve chest. When the valve gear moves through the next cycle, the stem wouldn't be able to move forward. That may not be the cause of the bind, but it's probably the easiest to correct, and would, at worst, eliminate one possible cause of the bind.
doctorwayne Rich, the drivers appear to be in-quarter on both sides, but that left side eccentric crank needs adjusting. In its current position, the motion through the connecting linkage means that the movement imparted to the valve stem occurs at the wrong time and may actually be causing the free end of that valve stem to drop out of the valve chest. When the valve gear moves through the next cycle, the stem wouldn't be able to move forward. That may not be the cause of the bind, but it's probably the easiest to correct, and would, at worst, eliminate one possible cause of the bind. Wayne
Do you see any signs of wear on the rear driver bearings or frame?
Soo Line fan Do you see any signs of wear on the rear driver bearings or frame?
richhotrain ....Is that the correct position? Rich
....Is that the correct position?
Yup, that's it.
richhotrain Normally, the loco runs just fine, even at top speeds, with no jamming or lockups whatsoever. It is only when a derailment occurs, and that is not often - - only through operator error on a turnout. However, the fourth set shows much more lateral movement, touching the plastic cover plate. It is my feeling, right or wrong, that when the loco derails, the lateral movement of this fourth wheelset reaches the plastic cover plate, whereas when the loco is on the rails, there is little lateral movement. This excessive lateral movement of the fourth wheelset causes the eccentric rod to jam and bend, knocking other connecting rods out of position, locking up the entire set of 8 driver wheels. I still cannot help but wonder if the square bronze bearing on the left side of the fourth driver wheelset is not machined properly, causing this whole series of catastrophic events. If I can figure this out, I will get back to everyone. Rich
However, the fourth set shows much more lateral movement, touching the plastic cover plate.
I still cannot help but wonder if the square bronze bearing on the left side of the fourth driver wheelset is not machined properly, causing this whole series of catastrophic events.
Rich, I don't own any steam but have been following this thread with interest. I see your logic in your analysis...if it runs fine but only locks up on derailment, then the jolt from the derailment might be causing hings to dislodge.
Instead of trying to replace the bearing, could you try to make the slot it fits into smaller, thereby keeping more secure? I was thinking to add small strips of styrene to the slot the bearing fits into to reduce its size. If you could find away to temporarily secure the bearing better, it might help point to the cause.
- Douglas
Rich, on the issue of the eccentric crank position, a couple of considerations basis my Athearn challenger learnings, recognizing there may or may not be similarities. On the Athearns, IIRC the eccentric cranks fit on the driver bolt in a special way; i.e., the bolt has a portion near the threads for the nut that is not round, but oval or ellipitical. And the similar shape hole in the eccentric crank therefore has to fit on one way or 180 degrees opposite to that. That fixes the eccentric crank relative to the driver so the crank can "drive" the eccentric rod to the valve gear. I mention that because if yours is similar in design the crank bolt hole posssibly could have been rounded out which could allow it to get out of position or have movement relative to the driver. If so, I'm not sure if it would be more suceptible to binding or other issues. Just a thought, but perhaps unlikely as your loco normally runs fine.
The other point is I didn't know what to do for driver bolt wrenches as when I measured the bolt head of one it didn't seem to fit any of the Micromark wrench set items so I didn't know what to get. The Athearn spare driver (w/o tire groove) came with the appropriate wrench for the challenger and big boy driver bolts but I still don't know if my other steamers would require special or typical small metric wrenches should I have to fiddle with them.
Thanks, everyone (Wayne, Jim, Paul, Doughless) for your recent replies.
I called BLI again today to discuss the problem with the loco. BLI is going to send me new springs to replace the current ones under the driver wheels. Some, but not all, of the springs have weakened significantly. I am not sure if that is part of the problem, but it can't hurt to replace them.
I also spent considerable time running the loco today at various speeds including the highest speeds. No problems, no lock ups, no derailments. The most recent derailment that prompted me to start this thread was on a faulty turnout that I have now replaced on the layout.
So, that is where the situation stands as of now. I am not sure what to do about adjusting the eccentric rod and crank. I don't have any mini wrenches and I am not sure how easy or difficult it will be to adjust the position of the rod and crank. I have not yet checked further into the wear issue on the bearing or its surrounding housing. I may wait until the next lock up occurs or until the new springs arrive, whichever comes first.
That's all I have to report at the moment.
richhotrain ...I am not sure what to do about adjusting the eccentric rod and crank. I don't have any mini wrenches and I am not sure how easy or difficult it will be to adjust the position of the rod and crank....
Rich, in lieu of a wrench, square-tipped pliers will do the job. Use the end face (not the side) of the pliers to firmly grip that hex-head screw on the flat areas opposite one another and twist counter-clockwise to loosen. You should then be able to remove it using your fingers only.Re-align the eccentric crank, then re-insert and tighten the screw.
Ask Santa for a stocking stuffer for Your tool box.....they work great,especially working on R/C Models and Trains I like them more than a wrench:
http://www.micromark.com/4-piece-nutdriver-set,7450.html
Rich, it sounds like you have received lots of good advice so I won't try to add too much, BUT apparently Broadway makes a "thumper" now and then as well.......?
I had two BLI mikes with similar problems, binding side rods, which eventually required both locos to be carefully fully dis-assembled and rebuild from the ground up.
Problems included drivers out of square and out of quarter (very slightly) and general poor fit of thesame parts you are discribing.
Back then Braodway offered me no soultions at any price other than to sell me some incorrect parts (from a different production version, little axle bushings installed in the opposite direction) which I used as a basis to create the correct parts.......
So your problem does not surprise me in the least.....
Sheldon
Sheldon,
Actually, the problem with my BLI loco is similar to a problem that I experienced with an Athearn RTR loco where one of those square bearings would not stay in place. With the Athearn, the bearing continually slipped out of place whereas it only seems to happen with the BLI following a derailment. BLI did offer to repair the Mike for $65, but they would use parts from the newer Paragon 2 line whereas my loco is from the older Powerhouse series. So, I said, thanks but no thanks.
When it first used to happen, I thought that the connecting rods were binding and bringing the loco to a dead stop, falling off the track in the process and bending the eccentric rod.
But, I soon realized that it always happened on a turnout, but never on a section of flextrack. So, now, I am convinced that, upon derailment, as the loco wheels lift off the rails, the bearing slips out of place and causes the rods to jam and lock. When that happens, I have to remove the driver wheel assembly cover plate to release the connecting rods and put the bearing back into place.
While I am waiting for the new springs from BLI, I will do nothing unless there is another derailment. Once I get the springs, I will open up the assembly to replace the springs and then closely examine the bearing and its housing.
Fortunately, derailments do not often occur anymore as I have considerably improved my track work (and reduced operator error). The most recent incident was caused by a faulty turnout which has since been replaced.
I still need to consider messing with the positioning of the eccentric crank.
I thought that I would update anyone who is interested in this problem with my BLI Mikado.
BLI sent me replacement springs for the driver wheels. With my trusty Optivisor and my Kadee spring tool, I removed and replaced the springs. The originals were filled with gunk and were not functioning at all. Now, they work to cushion the driver wheels as they move up and down.
Next, I examined the bearings and the housings for the bearings. I saw no obvious wear, but there was a lot of lateral movement on that last driver wheel set. So, I took two Kadee washers and turned them into split washers and fitted them over the axle between the wheel and the bearing on each side. That really cut down on the lateral movement.
Last, I was able to adjust the eccentric crank back into place.
Now, it runs like a champ, but time will tell if the fix was permanent.
Thanks to all who offered advice and, in particular, Wayne for the eccentric crank advice and Paul for the split washer suggestion.
Hi again, Rich,
First, thanks for providing followup info as it's instructive for us all.
Second, I'm glad you probably have the issue fixed but have a question...when you say it runs like a champ, does that mean it is not acting up in situations it did before? Or is it derailing less? If so, do you think the springs and/or lateral movement were key to that? Of course, I kinda doubt you have set up a test program of intentionally derailing it so it rolls over to see if the eccentric rod binds!
Third, I wonder if this is a problem to that series of locos (did BLI comment on this?) or unique to your loco? As I mentioned earlier, my older BLI mountain series, per my LHS guy, had some definite problems with the springs and/or journals that usually needed correcting. And my more recent BLI mikado has not had your problem...thus the question.
So if you have any insights on the above, great, but as I already said, thanks for closing the loop and glad the persistance seems to have paid off!
peahrens Hi again, Rich, First, thanks for providing followup info as it's instructive for us all. Second, I'm glad you probably have the issue fixed but have a question...when you say it runs like a champ, does that mean it is not acting up in situations it did before? Or is it derailing less? If so, do you think the springs and/or lateral movement were key to that? Of course, I kinda doubt you have set up a test program of intentionally derailing it so it rolls over to see if the eccentric rod binds! Third, I wonder if this is a problem to that series of locos (did BLI comment on this?) or unique to your loco? As I mentioned earlier, my older BLI mountain series, per my LHS guy, had some definite problems with the springs and/or journals that usually needed correcting. And my more recent BLI mikado has not had your problem...thus the question. So if you have any insights on the above, great, but as I already said, thanks for closing the loop and glad the persistance seems to have paid off!
Installing the new springs definitely permits the driver wheelsets to hold the rails better, and installing the split washers has really limited the lateral movement. Now, the square bearings remain in place, inside their housings.
The one thing that still concerns me is the movement of the eccentric rod and crank.It still seems to have too much play. When I talked to the technician, he did not acknowledge any widespread problem with the connecting rods on that first run of Mikados.
Time will tell if this is a permanent fix.