The Bumblebee Mk2 - a new traverser for Farthing

I’ve built a new ‘one-size-fits-all’ traverser for my Farthing layouts. 

My latest layout - The Stables - has two levels, so I needed a traverser which could accommodate that. After I had proposed various harebrained schemes, Stu Hilton suggested the principle that I have sketched above. This was clearly the way to go. But how?

  

After mulling it over I looked at my old traverser (above) and realised that I could kill two birds with one stone. I prefer to have just one traverser for all my layouts, and the old one has served this purpose well. I called the old traverser “The Bumblebee” because it defied all sorts of basic engineering principles – yet still worked. 

The old Bumblebee was nevertheless beginning to show signs of wear and tear, so I decided to build a new one that could serve all of my layouts, including the new two-level one. For this version I used wood instead of foamboard. With woodwork I just sort of bumble along, so the 'Bumblebee' moniker is also appropriate for Mk2 !

On Mk1 I used tubes to guide the traverser. It worked but was noisy, which led to certain domestic tensions when my wife wanted to watch TV and I wanted to shunt! So I found these “linear sliding guides” on ebay instead.

While not as silent as I had hoped (woe is me!) they do slide nicely. The angle braces are from various strata of my “can’t be bothered to sort all this” drawer. Masonite from a broken Ikea frame.

Adjustable legs from a Danish timber merchant. I have now standardized on them for my layouts. The rubber pads are a heavy duty type from 3M, essential as they prevent the legs from sliding on the tabletop.

The cassette was re-used from Mk1. One end of it serves my three single-level layouts (track 1-5). The other end serves the new two- level layout (track 6).

In order to serve all the layouts, I had to come up with a simple way of shifting between regular single-level operation on my existing layouts, and two-level operation on the new layout. To accommodate this, I made the cassette hinged. When shifting to two-level mode, it is tipped to one side, a strip of cork is placed on the wooden blocks, and the cassette is tipped back in place. The adjustable legs are then raised on one side of the traverser only.

With this, Stu’s original principle has been achieved: Rising gradient, level track.

For operation, traverser and layout are simply pushed together. The 3M rubber pads prevent any sliding. The adjustable legs make vertical alignment easy.

At the bottom level, a simple stop block is used to ensure that the cassette stops in the right place. This can be rotated down when the traverser is used on my other layouts. 

At the upper level, the traverser is stopped automatically as it reaches its outer limit. To avoid the cassette sliding down from this position, I have tentatively fitted some slightly tapered wooden blocks beneath the cassette deck. When they engage the angle braces there is a slight resistance, enough to hold the cassette in place. I'm wondering whether this particular solution will last, but let's see.

I have tested the traverser on all the four Farthing layouts, and so far I’m pleased with the operation. Here it is working the Down Bay on the (extendable) dining table. The stop block is a recycled kitchen sponge, which squeezes into place. As you can see I am not one to worry about scenic breaks!

With the traverser done I can now run trains on the new layout .  Below is a 1-minute video to celebrate.