TranzDeck whole-train HO elevator

I built a train lift (elevator) to carry trains from lower deck railroad to upper deck staging in the around-the-walls shelf layout.

It works.

The lift goes up and down, then the loco rolls off and stops halfway on and off. The operator then tries to operate the lift but the lift refuses to cut the train in half. the loco then rolls back on the lift and goes up and down again. (Track not laid at the top exit yet).

The name TranzDeck is a pun on our national railways, which in a previous incarnation (it's a long story) was called TranzRail, and the TranzDeck logo is a ripoff of theirs.
I had been wrestling with the track plan to cram staging, mainline, city, port and a steam museum into a little 10'x10' study, and I decided that to have what i want the staging just has to be on a second level with the main deck flat, not
consumed by lots of up and down grades to and from the staging. So then it came down to a few options:
1) helix: just barely possible round the water heater in the laundry next door or even outside in a purpose built enclosure, but both are enormous engineering challenges
2) a switchback up and down the wall: workable but tedious to use manually and a beggar to automate
3) a train elevator, which is where my thinking has ended up. I found this http://www.ospreyweb.pwp.blueyonder.co.uk/kmr/projects/trainlift-01.htm
(I loved the "After several minutes of careful planning and design").
I also checked out ro-ro. I love it and it was a major inspiration to me. They got eliminated on the base cost. I'm paying with "South Pacific Pesos" - it takes me more hours to raise that kind of cash than it does you guys) plus the enormous cost of shipping out here to NZ. So yep if I was a Yank I'd be giving them a close look [;)
I also looked at the wooden-wheel lift at Squirrel Valley. I liked the idea but it once again lifts at just one point and depends on a smooth ride in the guides not to cause any vibration. I'm not that precise in my engineering that I would back myself on this one (in fact I'd define myself as a sloppy hack). Also I'm trying to squeeze the lift in minimum real estate

This is actually TranzDeck II. For the long story of the first attempt see the Model Railroader forum

Track power is delivered to the deck, and turns off if the deck is moving. Power to the deck approaches can be turned off if the deck is not there. But I don't use this: it simplifies the wiring between sections if i don't, and think about it (as I finally did): with a single-ended deck, half of all trains will be backing in so the dead section has to be over 2m long, which doesn't work in a layout this tiny. I may use it to operate signals one day.


The deck won't move if anything is detected in the doorway to the deck (three IRDOT detectors from MicroMark, one at each approach door and one on the deck just inside the door).


Mechanical barriers descend when the deck is not there to stop someone shunting into space.
The frame is a vertical sheet of 12mm pine plywood stiffened on the front with 20mm x 200mm pine boards and on the back with cheap batten strips (about 20mm by 50mmm) with a coat of primer.

The drive is part of an old ATM machine that used to raise the protective sheet of glass from the screen/keyboard (remember those?), about twenty bucks. It is built for 20V DC. I run it on 24V at about 3A. I started with 12V which was nice and slow, but it was too wimpy to handle the variation in loads ebtween an empty deck and one with two trains. At 24V it does what it is told and quickly, but still there is only just enough power. The deck is steady enough that the extra speed doesn't derail anything (so far).

ATM sliderATM sliderThe runners are like oversized kitchen drawer slides, also ex-ATM, also about twenty bucks. Find your local ATM wrecker.

The lift deck is attached to an odd-shaped vertical plywood carrier attached to the drawer runners which are attached to the larger ply panel.


The deck-carrier is counter-balanced on lawn-mower-starter-cord (low stretch) through marine pulleys to an old window sash weight from the local scrap metal dealer, sawed to the correct weight/length.
End of motion stops are just bolts into t-nuts that lock into the wood. i wish i had put a wedge-shaped alignment plate to centre the deck top and bottom. haven't needed it so far but there is potential for the deck to move a millimetre or so left or right.

Track alignment is controlled by Atlas rerailers. I fill them with two-part Araldite epoxy glue on the outside of the rails to hold the rails even more solidly than they already do, reduce the flangeway clearance with thin strips of styrene, then I saw them in half widthways. The rail ends are lightly filed to a rounded edge so as not to pick a wheel. The halves are glued down with caulk, aligned with each other each side of the gap, with minimum clearance between, about 2mm. they do the same job as soldering the rails to screw-heads or to PC-board strip, but the half-rerailers do of course also rerail anything not perfectly on track as it apporaches the gap. perhaops i should use them the other way round to rerail anything that comes off? Or better, add another half rerailer facing the other way outside them.
On tours i have photographed a number of bridges, liftouts and modules that all work fine and none have closer clearances than i do and most have wider gaps, so i am pretty confident.
Tran
Control is by a single heavy-duty DPDT centre off switch. There are lots of LEDs to show what is going on since the tranzDeck is normally hidden away. There is also an override switch: if a train trips a fourght IRDOt at the dead end of the deck the IRDOT shuts track powwer to stop it running into the end. the reset switch overrides the IRDOT to allow the train to be driven away.

power then has to find its way thru a perf-board full of relays that provide the safety interlocks on both lift motor power and track power, triggered by the IRDOT detectors.
The control circuit is simple but effective
TranzDeck basic control schematic

The wiring diagram is not so simple
TranzDeck wiring diagram

Status

The deck moves and stops. the safety interlocks work. The control panel is built. The PC video camera watches the deck. trains roll on and off reliably (so far). the deck is covered in.

To do:

the IRDOT detectors are very sensitive to changes in ambient light - much tuning needed.

the relays chatter as a train passes - need to modify some fo the IRDOTs to a more diagonal angle across the tracks so they stay on as cars pass.

the video camera needs more light to see: install a few high intensity white LEDs running off the IRDOT power supply.

Maybe install a second DCC track feed so there are separate feeds to each deck track, to support transponding identification of trains in the TranzDeck. The problem with this is there is only one relay circuit turning power on and off to the deck. if I put in two feeds I will probably not bother to control power to the deck. If we don't intsall a second feed, transponding will still identify both trains on the deck and the camera will show who is on which track.

[UPDATED August 2009: I've made the tough call to retire the TranzDeck. I proved it works, but I am making a rod for my own back with the maintenance and operation of it. the upper deck is almost impossible to operate trains on, due to its height, and the TranzDeck accessibility for maintenance is terrible. In a more favourable location I'd do it again.]

Lessons learnt

  • It is not the mechanism for moving the track that matters. That bit is easy. What matters is the mechanism for steadying and aligning the track.
  • The most complex part is all the safety interlocks to prevent someone shunting into space or cutting a train in half with the lift.
  • You can't have too many rerailers in hidden track or fancy devices like train lifts
  • You can't over-engineer track that moves. if in doubt make it heavier, more powerful, more rigid, more controlled.
  • work out the counter-weight with the deck loaded with trains, not empty
  • make sure the deck is accessible for maintenance
  • use a powerful motor. Next time I'd use a 220volt linear garage door drive and to hell with the high-voltage risks