Railbus Frame
Nelson Riedel, Nelson@NelsonsLocomotive.com
3/20/2017, last updated
The frame was constructed over two years ago and many of the drawings were out of date.   I've tried to bring everything up to date but errors likely abound.  If you find something that doesn't seem to add up, you're probably correct.  The primary reason for providing this information is to give ideas to others who might want to undertake a similar project. 

Before attacking the frame a bit about the big pieces.  The roof or lid is held on by two bolts at the back which also serve as the hinge pins.  The nose consisting of the cab and engine compartment is retained by two screws.  The main body has four studs that extend through the main frame and is held in place by four nuts on the underside.    It takes about ten minutes to get down to the fame and motors, batteries, etc.  Note that the length is shown as ~62" and I said in the overview that I needed to keep the length to 66" to fit into the Escape.  The couplers are missing in the drawing above which will bring the length to ~66"

Many of the drawings contain details that are hard to see on the webpage --- especially for us old folks.  I'm including pdf files of the more interesting drawings.  The PDF can be downloaded by clicking the link: Railbus.pdf .  The image can be viewed in pdf viewer software such as Adobe Acrobat or Foxit pdf viewer. The images are easily magnified in the viewer and the image can also be printed from the viewer.   

Larry Simoneau gave me some advice on batteries and chargers.   He's had good luck with the WalMart Deep Cycle batteries and also recommended a charger --- more about the charger later.   One of the decisions was do I want to run on 12 volts, 24 volts or 36 volts?  Most the small locomotives use 24 volts and most of the small motors operate well on 24 volts.  With batteries, the cost per unit of capacity is reduced as one increases the physical size so bigger is better.  I found that there was room for two of the the WalMart maxx EverStart 29DC batteries with the properties described below.


The 61.7 lbs is more than I expected but they do contain lots of lead.   There are similar size 29 batteries available from other suppliers with the same footprint but most that I've found are not as tall.  The overall capacity is not indicated in the published  specifications; data on the Internet suggests that the capacity is 100 to 125 amp hours.  I've had the first set for three years now and they seem like new.   Of course, no activity in the winter here in Ohio unless I use them for ice fishing.   The batteries are connected in series to give 24 volts.

The image above gives the general layout (File: Top).   The batteries and motors will bring the weight to well over 100 lbs.   The other components, front truck and body bring the total weight to about 200 lbs.  The engineer is pretty skinny but wears very heavy clothes so that will add over 200 pounds more.  Fortunately the wife is very slender so we can plan on a total weight of 500 to 600 lbs.     That sort of weight calls or a robust frame; we don't want a swayback Railbus.    

Now we're getting down to the details (File: Frame).  I had some 1.5" angle and 1.5" channel so that is what I used.   The two channels at the back and the two over the front truck have the legs pointing up.  I milled 1/8" off  the legs that fit under the side angles so the top of the legs between the angles are even with the top of the side angles.   These channels were bolted in place with one 1/4" bolt on each end of each channel with the nuts on the bottom.  Once everything was square I tack welded each channel in place.  (I'm not much of a welder.  Bolting things in place and then tacking them with my flux-in-wire welder works for me.  All welds are on the under side and hidden from the view of real welders.)

The top of the front angle is notched so the horizontal part is even with the horizontal part of the side angles.  The joints between the front and side angles were then butt welded on the under side.             

The square tubes reinforcing the side angles were then bolted in place using 1/4" bolts that also go through the ends of the three channels under the batteries.  After the tubes were secured with the 6 bolts they were tack welded to the side angles.   The last two angles at each end of the battery area were then installed and secured with 1/4" bolts at each end.          
Photo on right shows the frame after the the drive module was installed.   Of interest here is the spacers between the sides of the battery and the frame angles.  That is 5/4" (1" actual) Trex deck planking left over from a deck project.    The spacers extend  under the angle for 3/8".  The bolts holding the channels and angles under the batteries were loosened  to get the Tex under the side angles and then tightened to hold it in place.   Note the heads of the bolts holding the channels and angles; I used hex head bolts and tacked welded the heads so it was easy to install the Nyloc nuts below.  Turns out that part of those heads interfered with the frame for the body so I had to grind off part of the heads.   Next time I'll use flat head bolts.

A big worry is that the batteries  become loose and turn into battering rams.  The spacers on the sides and the angles at each end of the batteries keep them from sliding around.  There are also clamping bars over the top of each battery to hold it down.

After everything was constructed I found that the dive compartment at the back is a really tight fit .  The battery area consisting of the three middle channels and the angles just in front of and behind the three middle channels can be moved forward by 5/8".  Wish I would have figured that out during construction.   

The front truck is identical to those described at Arch Bar Trucks .  Any style truck can be used but the arch bar is appropriate for the era.  The frame is equipped with ball bearings on each side that ride on the upper spring plank to keep the bus stable and permit easy rotation of the truck.     

I got tired of making drawings so used a couple photos to describe the front.  That is 1" X 1/8" flat stock and then 1" X 1" X 1/8" angle below the flat stock.   The angles and flat are held in place by screws through 1.5" channels centered 1.5" from each side.      
This photo taken from under the right front corner shows the vertical channel used to hold the angles and flat sock on the front together. Looks like I tack welded that channel in place too.  The foot pegs  are attached to another piece of 1.5" channel.   The channel with the foot pegs is held to the front with a couple screws; those button head screws visible on the previous photo.  Part of the lower leg of the foot peg channel directly in front of the wheels interferes with the wheels and has to be ground off. Things are tight under there. 

The foot Pegs are from www.heeters.com,  #ET-17-1270. 

Note that I didn't hose down the underside --- it's winter and the hose is frozen.  I did wash off the top as the dirt looks much worse in the photos.   
The rear platform is the next thing to describe (File: Platform).  Angles 1" X 1" X 1/8" make excellent steps.  The angles are sandwiched between 1/8" plates and tack welded in place.  The entire assembly slides over and is attached to the 2" X 1" tube that is used as the coupler pocket.   A couple screws and the coupler bolt holds everything in place.       
This shows the under side with the sloppy but effective tack welds to hold the steps in position.
This side looks better.    I was skeptical of the railings but they seem to be robust and make it look like a real platform.
This shows the slide out foot rest in the out position.  When retracted it becomes a footboard.

This photo was taken a couple years ago when I was painting the frame.   The square tubes sticking up are 1" X 1" X 1/8" and go up 10" above the deck.    They are attached to the 2" angle and against the outside angle.  I think I bolted them to the 2" angle and then tack welded themThey are sticking up and waving in the breeze necessitating the  angle braces made of 3/4" X 1/8" flat stock.  That is 1/8" (11 gauge) plate covering the front deck and attached to the vertical tubes.  The  charger is attached to the plate on the vertical tubes.  The charger is fairly heavy hence the robust mount.  Those side braces are 3/4" X 1/8" flat stock.  The grate in the deck is to permit air flow when the charger is doing its thing.  Note: if the three channels and two angles supporting the batteries are move forward 5/8" as described earlier, the height of the two tubes holding the charger must be reduced to 7.5" to prevent interference with the body.  The top of the posts would then be even with the top of the plate between the posts. 

The truss rods are 3/16" and the turnbuckles were originally threaded #8 but are easily enlarged to 10-32 (I only have10-32 left hand taps and dies).   The posts are 1/4" square and extend down 2.5" below the frame.  I drilled holes through the tube that is attached to the frame angle to get enough length against the inside of the frame angle to make a solid attachment for the front posts.   That front post is roughly in line with the center support channel for the front battery.   Things are a little crowded towards the back.  The channel holding the rear foot pegs is attached to the frame angle-tube combination with pieces of angle.  The front of the channel holding the pegs is aligned with the front edge of the middle support channel under the rear battery.   The rear truss rod post is attached to the foot peg channel.      The rear end of the truss rod is attached to the side of the rear axel journal rail. 

The four rods sticking up are used to clamp the batteries down.  The rods are 3/8" diameter  with the ends turned down to 1/4" and threaded 1/4-20.  The bottom end of the rods go into the middle channel under each battery.    Another piece of 1.5" channel is between the tops of each pair of rods to clamp the battery in position.  

This covers the frame except for some cosmetic details mentioned in the Body section and the rear axel described in the Drive section.  


Additional design information is at the following links:

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