Building a robust lift up section to access the railroad

In response to a request over on the O Scale 2 rail forum I’m posting here how I built a hinged 30” lift up section.  But first allow some context as to why I needed a lift section.  Influenced by my late friend John Armstrong and experience gained with operation of my last railroad (see March 2000 Model Railroader) I designed the current O scale railroad for no duck, walk around operation.  To provide relatively  long runs without multiple trains in a field of view, the track route follows the perimeter of the room and then folds down the middle on itself several times.   Double sided backdrops are used to prevent viewers from seeing other trains and track across the room.  IMO these elements along with hidden staging yards at each end of the railroad serve to enhance the illusion that the trains are actually going places over great distances.  The steps and outside door into the basement are outside the area allotted to the railroad.  The attached plan shows the general arrangement of the room, the track plan, and the location of the access point.  With a track route in part along the perimeter of the railroad area some means of no-duck entry needed to be provided  - thus the need for a lift up, drop down, or swing out section.  Due to the complexity of the track in the area I chose to access the railroad I decided to use a hinged lift up section.

The lift section had to be rugged and easy to operate as all visitors and operating crew must enter through it to see/run the railroad.  Multiple super elevated curved tracks and a branch line turnout are mounted on the lift section, requiring an added degree of precise alignment for smooth operation..  For strength and stability I framed the lift section using 1x4’s topped with a good grade of ¾” plywood – similar to the framing I used on the approaches to the lift section.  Perhaps I could have used lighter framing but I didn’t want to chance issues with warping.  The opening end of the lift section box frame was angled slightly at its base to provide clearance as it rises past the fixed benchwork.  I used a set of medium duty 3 ½” hinges purchased at my local Ace hardware – ones with minimal play.  A key point - hinges for model railroad lift sections should be mounted such that the center line axis of the hinge is at or above rail height.  This is required so the rails on the lift section do not hit the approach rails during lift.  To this end I top mounted the hinges on plywood blocks screwed and glues to the top of the lift section and closed end tabletop.  In my case ¾” plywood blocks provided the needed clearance for code 148 AtlasO flex on ½” Homosote roadbed.  At the open end of the lift section I bolted short pieces of ½” bar stock to serve as vertical limit stops when the span is in the down position.  I mounted a small door stop on the backdrop for the lift section to rest against when it is in fully raised position.  My initial horizontal alignment & locking mechanism was a simple top mounted hardware store slide bolt.  With the structure complete and in the down and lock position I nailed/ glued 48” long sections of Homosote roadbed in a continuous fashion through the adjacent fixed approaches and across the lift section in smooth curves.   When the glue was fully set I cut the roadbed at the ends of the lift section with a utility knife.  Some additional roadbed removal with a coarse file was required at the open end of the lift section to provide lift clearance.  In a similar manor I laid the flex track through the area - cutting the rails at both ends with a Dremel cut off wheel - only after making sure I had smooth curves through the area of the lift section.  Rails at the open end of the lift section were cut at a slight angle toward the hinge end to provide clearance during lift.  I found that a rail top gap of about 3/32” works well..  To minimize the risk of a train crash with the lift section in the “up” position, I gapped all the tracks approaching the lift section several feet back from both sides of the span.  Hidden micro switches power the gapped rails when the lift section is in the down position.  A remaining risk is someone backing a long train into the void with the lift section up.  With engineers walking with their train along the route hopefully this won’t happen.

 All my equipment rolled smoothly through the lift section – for about 6 months – then Williamsburg, Virginia’s humidity hit with full force.

The open end of my lift section connects to a free standing length of benchwork about 50’ long.  Despite insulated walls, reasonably decent lumber, good HVAC, and a dehumidifier I discovered that the layout in the area of the lift section would move back relative to the opening around 1/8” with change of season.   Since the movement is 90 degrees to the direction of the track this played havoc with alignment of the rails at the open end of the lift section.  I should note that the hinged end benchwork doesn’t move at all as it is attached to a wall tied to a steel house support column.   Compounding the problem were the lift section hinges.  Being “tight” they didn’t provide enough lateral play for the slide bolt to pull the lift section into alignment at the open end.  My first attempt to address the displacement issue was to replace the wood legs under the open end with a rebar reinforced cement block support column.  The existing benchwork was attached to the block column by threaded steel rods to provide for leveling and fine height adjustment.  For a few months this worked - until the next seasonal change when it became apparent that even short sections of 1/2” steel rod will deflect when faced with changes in lumber due to moisture in the room.  For a few years I lived with the problem by slightly shifting the flex track on the open side of the lift section – twice a year.  OK with un-ballasted track but not workable with ballasted roadbed.  A permanent fix called for adding some lateral play to the lift section at it’s open end, while maintaining positive alignment when locked down.

 The approach that worked was to introduce some lateral movement of the lift section by slightly reducing the diameter of one of the two hinge pins – perhaps ten thousands of an inch.  The other element of the fix was to use a robust slide bolt to lock the lift section into alignment at the open end.  For this a friend machined a ½” steel rod with a tapered point on one end.  The shaft was mounted  to the underside of the lift section by a pair of relatively low cost imported pillow blocks (found on eBay) and cross drilled for a throw handle. Attached to the face of the open side of the fixed benchwork was an aluminum plate drilled to accept the slide bolt.  The arrangement been in use for several years and has performed well under heavy use -  especially with providing easy duck free access to the railroad during  layout tour/open house events.    

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Ed Rappe