Frank's suggestion would work, but for this roundhouse you would still have to remove the apron. The stall tracks fit in slots, so they are locked in the position you see them.
Turntables require precise alignment to avoind derailments, too. I would worry about getting that exactly right if I were trying to use curved approach tracks and stall tracks.
I like Rich's suggestion. Get the Walthers roundhouse.
It takes an iron man to play with a toy iron horse.
Quite frankly, if the OP has the Walthers turntable, he should install the Walthers roundhouse. They are designed to be compatible with one another.
Rich
Alton Junction
The closer you put the roundhouse to the pit....the less side clearance you have for the door openings. What is wrong with putting the rounghouse further away, if you have the room. The pit tracks would be straight...but they could gently curve, to match the roundhouse tracks. Whats built first, the roundhouse? Or the turntable? Real life of course.
Take Care!
Frank
Yes, I think we're on the same page.
It's been a while since I built this, but as I recall, the floor is a continuous piece from the edge of the turntable to the back wall of the roundhouse. At least part of the apron area would have to be removed. This will work with a 90 foot turntable, but if you've got a large one like a 130 footer, the apron would have to be removed completely, and the roundhouse doors would be right at the edge of the turntable pit.
Mr B,
My Walthers 90' TT aligns perfectly with all three stalls of my Atlas Roundhouse. I think you are describing that large grey extension(or 'apron')to the base of the Atlas Roundhouse. It sticks out 1.5" so that it will align with the Atlas TT. I just removed the grey extension and used some .040" styrene to replace it in front of the stalls. This allows one to get the TT/Roundhose alignment perfect. My TT is raised 3/16" to match the cork roadbed, and the Atlas Roundhouse aligns perfect. BTW, the stalls are 9.5" inside my Atlas Roundhouse(just measured them). If you remove the walk-way at the rear of the stalls, you will have 10" of clear space. Since my 'terminal' is not a large classification yard or division point(local engines 'live' there), the stalls are perfect for the GP9's and Bachmann 2-8-0's that 'live' there. It took me a few minutes of thought and a re-read of your post to realize that you were describing that 'apron' My 'engineering' just removed it as part of the 'site preperation'!
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
After giving this some thought and looking at my own Atlas TT and roundhouse, I'm going to have to sort of disagree with Jim. The stall spacing is, as he stated, 15 degrees, but that is based on a turntable diameter of 9 inches. If you set a Walters turntable to index at 15 degrees, it will not line up with the ends of the Atlas roundhouse tracks unless you cut back the apron. You could do that, but then there would be very little space between the turntable and the roundhouse doors.
I did some measurements. From the doors to the end of the stall tracks is 9 inches, so that's the maximum length locomotive that will fit with the doors closed. From the end of the apron to the doors is another 4 inches.
A 90' turntable in HO scale measures nearly 12 1/2 inches in diameter.
Be aware, though, that the Atlas roundhouse is short, because the Atlas turntable is only 9 inches across in HO scale. So, an engine that barely fits on the turntable will barely fit in the roundhouse.
It will work fine. I have an Atlas 3 stall roundhouse with a Walthers 90' turntable. The Atlas stalls are a 15 degree spacing. The Walthers turtable can stop at any position you want. Now, if you have an Atlas turntable and a Walthers roundhouse, you will have problems as the indexing f the Atlas turntable is set for 15 degrees and the Walthers stalls are set at 10 degrees....
Does anybody know if you can use a Walthers 90' TT with the Atlas 3 stall round house ?
Will the stopping points on the TT meet up with the stall tracks inside the roundhouse , or do I have to use a TT and roundhouse from the same manufacturer.
Thanks in advance
Tom from Down Under.