On page 57, the layout appears to have a complete "O" gauge circle made up of 8 sections followed by 2 sections of O72. However on page 58, the wiring diagram labelled "Figure 2" has a different looking track arrangement. It appears to have O72 sections at the beginning and end of the circle.
Phrank - we built one of these about 10 years ago using the info from the old Lionel Display layouts Kalmbach book (out of print, hard to find, and typ expensive - and which someone unknown ran off with our copy). As the photo shows in Jan CTT the lead in track down uses two pieces of O72 curves to obtain a critical slight offset once in the tunnel to allow the entry into the O31 loop and achieve alignment with track at the exit.
If you examine the photo on P57 from an actual D27, you can see the O31 loop does not align with itself upper to lower which it would if the O31 loop radius was not altered. I cannot remember if we had to "open" up the O31's after the O72's to a slightly larger radius or if we had to "bend" the last upper O31's to a tighter radius. This is determined by the width of the layout (4.5 ft) which has to be gauged by the width of the hatch from photos we had from the book which shows more than the Jan CTT as I recall.
Again the alignment of the hidden loop tracks are necessary to get the "look" of the straight tracks in and out of the tunnel for the illusion to look right.
Now the fun. The O31 loop takes a lot of finessing as the 2035, one of the shorter Magnetraction steamers (important), with its fixed frame ends up with only 2 outer drivers - diagonally - touching the rails as the inner and outer rails on a curve on grade are not "level" to contact all the drivers in such a tight loop. The loop has the be very uniform on the grades for this to work.
The short, low, and light weight 8" 1002 style gondolas are also critical and notice there is typ no caboose or other cars. This is because most other cars "catch" the upper loop when passing under. The top of a typ SP caboose is about the same height as the loco and sometimes slightly taller. Recall the grades of the tight O31 loop must be very uniform and thus the loco just barely clears the upper track when passing under.
All of this is important if you are trying to meticulously duplicate the D-27. If you take some license with the width, length, depth, and the loop, then it will likely be easier to make it work and with more variety of rolling stock.
At the time our goal was to accurately replicate the D-27 for a customer.
The track must be kept meticulously clean. The cars must be very free rolling (not a characteristic of PW 1002's - newer MPC versions with "fast angle wheels" are better). Smoke fluid residue (oily) and oil on the track will obviously cause the loco to slip badly.
When it works it is great fun. Getting the loop to work and keeping it working was a challenge.
Good luck and let us know how it turns out if you take this on!
Regards, Roy
On page 93 of the referenced soft cover book there is a discussion of the "Disappearing Train Layout". It was built by Lee Price. He said the key was to use a 14" curved section of O 72 track and a special 10-1/2" curve made by cutting four notches in the tubular rails to bend it to accommodate the grade. Unfortunately there is no detailed track plan layout. Hope this helps.
Papa-D
I don't recall ever seeing a D-27 in action but I think it is one of the most fasinating display layouts ever designed.
"IT's GOOD TO BE THE KING",by Mel Brooks
Charter Member- Tardis Train Crew (TTC) - Detroit3railers- Detroit Historical society Glancy Modular trains- Charter member BTTS
sir james II don't recall ever seeing a D-27 in action...
Here you go!
The illusion is not quite complete, however, as the train is not long enough. A similar effect using a crossing track is very easy to do with a train that is not visible going in one side, and out the other side, of the tunnel at the same time.
Rob
Although the D-27 layout was built in 1950, I remember being amazed by one of them as a kid. Since I was born in 1959, it had to be around 1965.
The November 2001 issue of CTT has a four page article by Roger Carp on how to build the D-27 Disappearing Layout. It includes the track plan including a list of track required, wiring, and accessories. Perhaps most importantly it shows how to "notch" one of the O-72 track sections. As mentioned earlier, the train itself was a 2035 locomotive with 6001T tender, and 13 gondolas (3 loaded with barrels and the remainder empty. The was no caboose.
That is really neat. I've seen the plans but never one in operation
Thank you
Jim
Papa_D The November 2001 issue of CTT has a four page article by Roger Carp on how to build the D-27 Disappearing Layout. It includes the track plan including a list of track required, wiring, and accessories. Perhaps most importantly it shows how to "notch" one of the O-72 track sections. As mentioned earlier, the train itself was a 2035 locomotive with 6001T tender, and 13 gondolas (3 loaded with barrels and the remainder empty. The was no caboose. Papa-D
I recently bought that issue along with a few others in an effort to complete my collection. (I just need one more issue now, the May 2010 issue! CTT no longer stocks that issue, so it looks like I'm going to have to get it off ebay.) I haven't gotten a chance to go through it yet, so I didn't know about that particular article. Thanks a lot!
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