North Pacific Coast Railroad
HOME OF THE RAIL PUP
Roadbed Construction
by Ken Stanfield
This is the way I built my railroad.  Keep the ideas you like, discard the rest.  Every
railroad is unique - the materials, the route, the equipment and people – so do what
works for you. While I did much of the work on the right-of-way by myself by hand,
I would like to acknowledge the contribution of my wife, Pat, and David, Greg and
Troy Middleton.  With their generous help this railroad was finished a year earlier
than planned.

Planning was a big part of building.  While I had a general idea of where I wanted
the track to go,  the exact route needed to be established.  In order to do that, I set
some standards for the NPCRR.  

  • 2.5 inch scale for my equipment
  • 7.5 inch nominal gauge – 7.625 inches actual
  • 2.5 ties per foot – 16 inches long
  • 25 foot minimum radius to fit the property
  • Maximum grade of 3%
  • Number 6 switch frogs to match the minimum radius
  • Manually operated spring switches

Additionally, I chose one inch aluminum rail, slip-on rail joiners and composite
wood ties (Trex).  Each of these was a choice that affected the basic construction of
the entire railroad. Each choice had an affect on the ease of construction, cost and
long term maintenance.  The size of the equipment you can run is determined by
these choices.  You have to start with the basics.
Building the North Pacific Coast Railroad
I acquired some tools to help lay out the right-of-
way.  My major purchase was a contractor’s
sight level and tripod for under $100 from a
local pawn shop. I mounted an old tape
measure  to a 10 foot pole to use as a rod.  A
100 foot tape measure, some marking paint and
wooden stakes were also purchased.
In order to visualize where the track would go, I built three frames from PVC pipe
and fittings.  Two curved sections were built to a 25 foot radius.  Each frame is 10
feet (one track panel) long and 2 feet wide.  These were very handy when fitting
curves around obstacles where a string line from a center point is not possible.  
Also, by using a curve with the straight as an overlay,  the position of a switch could
be estimated.  I used a lot of marking paint on the lawn before moving any dirt.  If
you have to “sell” the right-of-way to the “boss”, this will help a lot – easier to see
where the track is going.
Steve and Nancy Dail ride the NPCRR
I then used the contractor’s level to verify that I could get from point A to point B at
3% or less. The right-of-way was marked every ten feet – five feet in critical areas
– next to the right-of way.  These marks are the control points for roadbed
construction.  Now you can measure the height variations along the centerline
between those marks and determine the grade change.  As you construct the roadbed,
you can go back to these same points and re-measure the results.  
Once I had the right-of-way selected and approved, I removed the top two inches of
material.  A rototiller works great for this.  Remove all of the material that can
decay under the roadbed. Remove large stones, roots and other buried debris that
might cause problems later.  Fill and compact any holes in the subgrade.  Next, put
down a layer of weed block.  Most of the time, a two foot wide section is
sufficient.  I purchased four foot wide rolls and cut them in half.  

Weed block does several things for you. As its name implies, it stops a lot of growth
from coming up through the roadbed.  It allows water to drain away, and it helps
prevent the gravel from disappearing into the dirt.  In my case, it also discourages
the moles from coming up in the right-of-way.

Building the roadbed should not be confused with ballasting the track.  Roadbed is
the material under the ties while ballast is the material around the ties.  Most of us
use the same material for both jobs, but the roadbed is the more critical to
construction.

The material I use is a 5/8 minus crushed rock which means that the largest rock is
about 5/8 inch.  The “minus” means that the material also includes crushed rock and
sand smaller that 5/8 inch.  In my area, this is the cheapest crushed rock available –
about $20 a yard delivered.  We used over 200 yards of material on the NPCRR so
cost can be a factor.  Use only crushed rock because you want it to lock together –
do not try to use smooth river rock.  If you live in an area subject to hard freezing
and frost heave you will want to use material without the sand or ‘fines’. The fines
tend to retain water that may freeze.
Once the alignment was established, the vegetation was removed in a two foot wide
path.  Weed block was installed – held down by a few nails.
This next step really simplified construction of the roadbed.  I used my contractor’s
level to determine the relative height at each mark.  This number was entered on a
spreadsheet and  processed to determine the depth of roadbed needed at that point.
Sample spreadsheet used to determine depth of material on right-of-way.
Click on sample  to download Excel spreadsheet

  • Mile Post – Measured in feet from a zero starting point.  I found
    either a five foot or ten foot spacing to be convenient.

  • Distance – the distance between previous and current Mile Post in
    inches.

  • Input Observed – the actual observed field measurements in inches
    – user input to closest 0.25 inches.

  • Actual “ – the calculated change in grade between previous and
    current Mile Post in inches.

  • Accum – Accumulated change in grade from 0 to current Mile Post in
    inches.

  • Actual% - the calculated grade percentage between previous and
    current Mile Post. Up grade is a positive number; down grade is a
    negative number.

  • Adjust Desired% - the user input desired grade percentage from
    previous to current Mile Post.  Up grade is a positive number; down
    grade is a negative number.

  • Desired” – the calculated field measurement of the finished roadbed
    in inches.

  • A blank column to write in the next observed field measurements.

  • Results Material Change – The calculated depth of the fill in inches
    needed at each Mile Post to provide the Desired % grade.  Ignore
    changes of less than ½ inch.  Positive number – add material; negative
    number – remove material.
With scrap wood, I built temporary depth gauges at each point.  These gauges were
held together by long spikes and were reusable.  By stacking various thickness
together, a gauge of ½ inch to over 4 inches could be assembled.  Gravel was then
filled in between the gauges, compacted and leveled.  The gauge would be removed
and the hole filled.  If necessary, the process was repeated at the same location until
the roadbed was at the proper height. A 12 foot 2x4 works as a screed to level the
material between depth gauges.

I built my roadbed to have a minimum of two inches of material under the ties.  This
provides excellent drainage and allows me to adjust the track panels up or down.  If
I had laid the track panels directly on the ground, there would be no way to adjust
down.
Compacting the gravel as you go is really important – just as a good foundation is
necessary for a house, it is also necessary for a railroad.  I am fortunate to have a
small roller and a sheep’s foot that I use for roadbed construction.  The sheep’s foot
is the more useful tool but a vibrator or a small water filled lawn roller should also
work.  I sprayed the roadbed with water to help it settle and compact.   Build deeper
roadbed in layers, compacting two to three inches at a time before adding the next
layer.
The process was the same in the woods; remove vegetation, put down weed block,
spread the gravel, compact and level.  A wider four foot path was built to provide a
walking area to facilitate maintenance.

My roadbed is very stable, providing a safe, smooth ride. Maintenance is seldom
more than eliminating the weeds and grass that sprout in the right-of-way. It will
provide years of low maintenance service because of the time and effort that I
invested in it.
For private use only – all rights reserved 2007
Last update 03/30/07
Be Safe.
If you attempt a project like this, you are responsible for calculating the load
handling ability of your roadbed.  Failure of the roadbed can result in injury or
death. The author and this website are not responsible for checking your
calculations or workmanship