Walthers 130 foot turntable help needed

[mike_lawyer]

Hi guys,

I spent the weekend installing a Walthers 130 foot turntable on my layout, and I am having some issues.  As far as rotational alignment indexing, everything runs flawlessly.  The issue I am having is with vertical alignment between the ends of the bridge and the approach track.

First, the pit is seated perfectly level in all directions, as measured by a large level spanning across the pit without the bridge installed.

I am using Peco Code 80 track for the approach tracks.  The problem I am having is that with the head of the bridge lined up with the approach track, the bridge track is slightly lower than the approach track, causing a noticeable "hop" when a loco enters/exits the bridge.  When the tail is lined up with the approach track, the bridge track is higher than the approach track.  Again, this creates a "hop" when moving a loco onto the bridge.

I am trying to figure out what I can do to level the bridge track with the approach tracks in either direction.  Again, the pit is perfectly level sitting in extruded foam insulation.

Appreciate any help or tips anyone has.  Thanks.

[nkalanaga]

I have no experience with the Walthers turntable, but it sounds like either the pit bearing isn't seated squarely in the pit floor, or the table isn't square on its shaft.

The first thing I'd check is the alignment at 90 degrees to the approach track.  If both table ends are at the same height there, and/or if the same side, relative to the approach track, is higher than the other on both ends, then I'd suspect the bearing.  From your description, this probably isn't the problem, as the table would be either higher or lower than the approach track at both ends.

if the table itself is tilted, the 90 degree results will be the same as the approach track - one end is higher, the other is lower. 

The cure would be to square up the table on its shaft, but without seeing the table, I have no idea what that would require.

[mike_lawyer]

Thanks, it's very strange.  The table is perfectly level, but it seems one end of the bridge is higher than the other end as it rotates. 

[nkalanaga]

Is the table supported only by the shaft and center bearing, or does it have working wheels at the ends, like the prototype would?  If it does, the wheels could be off at one end, which would cause that end to be higher or lower.

If it has pickup wipers at the ends, one of those could be bent differently, causing excess pressure, which would also tend to raise the bridge.

[mike_lawyer]

The bridge rides on a plastic ring rail that goes around the pit.  There is nothing in the instructions about modifying the wheels that run on the ring rail to modify the bridge height on each end.

[peteski]

Are the wheels/rollers riding on the ring rail touching the rail, or is one or both ends floating over the rail?

[mike_lawyer]

Are the wheels/rollers riding on the ring rail touching the rail, or is one or both sends floating over the rail?

Not sure, I will have to check it out tonight and report back.

[mike_lawyer]

As far as I can tell, the turntable is supported in the center post area and by the supports at both ends of the bridge.

[GGNInNScale]

Hi
One way to check is to use a spinning laser level (several makers- mine is a Makita).  The laser beam can be aligned to the center of the bridge at track height or very slightly below.  You can see the red laser beam easily.   Then, rotate the bridge and watch how the light beam moves on the bridge.  I just checked mine to be sure this would work.  My unit is level, and does not hop (this could occur if one of the end gears is not centered on its' axle".  But if you watch the intersection of the light beam with the rails you should be able to detect the problem.  Cannot tell you how to fix it, but you should be able to figure out what the issue is.  Good luck.

[mike_lawyer]

Well, to add to the problems, I am having problems with the turntable causing my DCC system to short out when the bridge passes through the dead zone.  Interestingly, it only does this when rotating in one direction.  I cleaned the contacts in the bridge post and the wiper contacts, and I can't seem to make it go away.

On the vertical alignment issue, one of my buddies has one of the original Walthers 130 foot turntables from the mid 2000s.  In comparing my friends bridge and the current version of the bridge, there is considerably more weight in the original bridge than in the revised bridge.  I think the older bridge additional weight helps keep the bridge level during rotation.  I don't know why Walthers chose to go with less weight except maybe for some cost savings.

I am going to call Walthers next week to try and diagnose the short issue.

[nkalanaga]

For the short, I wonder if the wipers are wider than the gap in the fixed contacts?  That wouldn't be an issue with DC, because the bridge power would be off while it was turning.  But with DCC always live, it would cause problems.

[mike_lawyer]

Yes, there must be something shorting out when the turntable is in the dead zone.  Not sure why, I will call Walthers this week.

Regarding the vertical alignment issue, it seems the new version of these turntables has less weight in the bridge than previous versions.  I am going to ask Walthers about that as well.