skinny N-Trak 4’ corner

by

Steve Gillett

                                    

A standard N-Trak 4’ corner module is 34” deep and 68” wide (tip to tip.)  A standard door opening is 28” to 32”.  If you do the math, you quickly see that a standard corner module will not fit through a standard width door without being rotated onto its back.  If, however, you whack 8½” off of the front of the module, (whack being an N-Track technical term for cut off) you end up with a corner module that is 25½” deep, and one that can easily be moved through a standard door opening without any special lifting or rotating.  A normal 4’ corner module is six-sided with a 34” x 34” square section sandwiched between two 24” x 24” right triangles.  If one 24” side of each triangle is reduced to 12”, the center square of the module becomes a 25½” x 34” rectangle and the module’s overall depth becomes 25½”.

           

This seems to be pretty basic logic and a no-brainer until you try to lay track and maintain the N-Track minimum radius curves on the red, yellow and blue lines.   I originally attempted to reduce the width of the module to 24” (which is the depth of a standard N-Trak module) but by doing that, the curve radii on the red and yellow lines has to be reduced to something below the 24” minimum N-Trak specification.  To maximize the curve radii, the track is laid with a 4” straight section, a 45Ί curved section, a 20½” long straight section, another 45Ί curved section, and a final 4” straight section.  This yields track curve radii of 25½” on the red line, 24” on the yellow line and 22½” on the blue line, all which meet or exceed N-Trak minimum radius specifications.  Unfortunately, there is insufficient space for a transition curve.  The focal points for the two curves are 4” in from the clamp ends and 29½” back from the short sides.  To draw the curves on the module top, clamp a shelf on the back of the module that temporarily extends the module surface back to the focal points, mark the spot and draw the arcs.

 

Note that this technique can also be applied to a 3’ corner module.  The dimensions are the same except the center rectangle is 25½” x 17” and the straight section of track between the two curves is only 3½” long.  Essentially the only difference is that a 17” section has been whacked (there’s that technical term again!) out of the center of the module.

 

In this track design, the red line long straight-a-way is only one inch from the front of the module.  It is strongly suggested that a piece of Plexiglas be attached to the module front to protect against any disastrous consequences of a derailment in this area.  The plus side of this is that, since the tracks are all the way to the front of the module, the room behind the tracks for scenery is maximized.  One side benefit of this design is that the skinny module is much lighter than a standard corner module.

 

The particular module shown in these photographs is Cushing Hub and is another example of the NEONS (NorthEast Oklahoma N-Scalers) efforts to depict realistic scenes from across the state of Oklahoma.

 

With eight major crude oil pipelines terminating there, Cushing, Oklahoma is the largest hub for the distribution of crude oil in North America. The Cushing pipeline interconnect is spread over nine square miles and has crude oil storage capacity of more than 33 million barrels (1.4 billion gallons).  The crude is stored in tanks that are spaced far apart to minimize the possibility that a tank which catches fire will ignite other tanks.  Dikes are built around the vessels to contain any fluids from a storage tank that begin to leak due to corrosion, lightning, or other damage.  These dikes, called firewalls, prevent those fluids from escaping and polluting the surrounding area.

 

In earlier days, when demand exceeded pipeline capacity, railroad tank cars were used to transport the additional oil.  On this module, a branch line exits the blue line and curves back through the skyboard to connect to a set-up track on the adjacent module.  This branch line has two sidings where tank cars once were loaded and unloaded.  Each of the 60’ diameter storage tanks has a capacity of over 16,000 barrels (672,000 gallons) of crude oil.