Gents,
I am planning to use the new Walthers 90' indexing turntable on my branchline layout, but I have a question about installing it. Can the pit be installed "at grade" instead of below grade, and the pit walls cut down to make the pit floor almost level with the terrain in a scene? The instructions describe mounting the pit by its flange in a hole cut in the benchwork...I am wondering if it can be rested on/attached to a flat surface instead.
The reason I ask is that my prototype had a turntable where the approach track and a short run-off track opposite the lead are 'raised', while the rest of the pit has no wall or lining, just a gradual grassy slope up to grade level. To model it, I would have to cut off all but about 15 scale feet of pit wall on opposite sides...rest the pit on a flat surface with a hole cut out for the motor...all about 1/2" below the grade of the surrounding terrain.
Thoughts?
Andy
As long as you maintain the integrity of the pit and the central well, including all the electronics in the housing below the pit, you will be fine. You can build a trestle up to the lip of the pit, or a raised roadbed, but you won't be able to alter the pit at all. Its wall houses an optical referencing device to "zero" the encoder that permits the indexing.
Yes, you can build up terrain so that the pit is actually above most of the surrounding terrain, and you can set the lip of the pit on that berm. However, it will take some doing. If you would like to merely have the whole side of the pit exposed, then it will look terrible as the pit is meant to be recessed into the "ground". However, you could use styrene to skirt the pit on the outer perimeter if you have to have it above grade. Just paint it to look like weathered concrete, and you should be fine.
I don't know if that is of any help, but you would not be able to substantially alter the pit and retain the integrity of the model. For one thing, and apart from the optical window I mentioned, contamination would eventually be a problem, and it might only be about spiders and other things getting into the works.
Andy,
You are one brave soul - Cut up a $300 turntable to match your prototype! I just looked at my 'still un-installed' one. You should be able to cut back the pit wall down to the rail/cogs that the turntable use to propel itself. The open or low side cannot be where the 'index' lamp is. So you will need to 'test fit' it to you location with the index lamp on the 'high' side of the fill. Good luck!
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
jrbernier wrote: Andy, You are one brave soul - Cut up a $300 turntable to match your prototype! I just looked at my 'still un-installed' one. You should be able to cut back the pit wall down to the rail/cogs that the turntable use to propel itself. The open or low side cannot be where the 'index' lamp is. So you will need to 'test fit' it to you location with the index lamp on the 'high' side of the fill. Good luck!Jim
No doubt! Won't you have to cut the bridge down too??
Lefty
I do already have the table in question. I got it on a good deal, so I'm not quite $300 in on the project. However, as ya'll have pointed out, it is a major investment that I do not want to screw up. My biggest fear about cutting down the pit walls is that the pit will become wobbly and lose structural integrity. Taking away the vertical 'bracing' from the walls might make it more pliable, which would impact the operation of the bridge. I THINK that the pit is thick enough plastic that it will hold its shape without the walls, but I'm unsure.
To answer some questions: Yes, the lead track will have to line up with the zero-ing sensor. This would match the prototype which had "abutments" basically where the lead and overrun tracks bordered the ring rail. No, I wouldn't cut down the bridge (I'm not changing the pit diameter, just the pit wall height in areas that don't have tracks, the approach tracks will be at the full pit wall height). No, I don't think the Atlas table is either big enough (has to spin a 2-8-0), nor realistic with that flat track-height floor. Yes, I think the look of the exposed bridge in a shallow grassy pit is worth modeling...aka worth risking the $300. If you knew the A&W, you would know how out of place a beautiful concrete-lined turntable would be! I'll try to post a photo to show what I'm getting at.
Any other thoughts? I'm thinking rotary tool to make the cuts...just above the ring rail. So, there will be a SHORT pit wall of about 1/4".
You have one critical error already in your assumptions....the "zeroing point" optical window on the sidewall of the pit is not to be closely oriented with any of your tracks...none of them.
-Crandell
I was wrong. My apologies....I had thought my recollection included keeping any tracks away from the zeroing sensor, but it was indeed the "no tracks" twin points where there is no electrical contact due the wipers being in non-powered gaps.
Again, sorry for that. You should be fine.