Building Engines and
rolling stock cars: construction tips
This document describes how to build engine and crank cars, and shows
details of parts, approximate part costs and suppliers. A typical engine or drive motor car
will cost less than $300 to construct; a passive car less than $100.
The picture below shows my Òoriginal engineÓ yellow coal car design which
pushes a passive orange engine and pulls passive passenger cars. The key to low cost construction is
using available 24-36 V 350-500 watt scooter motors and motor controllers, and
using lawnmower wheels instead of premade metal flanged wheels. This train is remotely controlled by an
adult operator using a simple car door opener key fob with 100 foot range. A Ònew engineÓ design is also
described that allows a 200 lb adult to sit on the engine and drive the train
(assumes filling pvc tracks with sand for more rigidity, which is not necessary
if only small children ride the train).
Making flanged engine drive wheels train
wheels:
A 6 inch wheel would use a 7 inch cutoff wheel to create the
½ inch flange. Larger
flanges (i.e. 7 inch flanges for drive wheels to be described below) can be cut
with a band or jig, saw rather than hole saw. Drive wheels do not rotate on their
axels; they are attached firmly to the axel to drive or rotate the axel. The usual method is to use a drive wheel
hub. I could not find inexpensive
wheel hubs for ½ diameter axels, so made wheel hubs from inexpensive 4.5
inch diameter V belt Chicago pulleys.
See pictures below.
Drill through holes
through the pulley, polypropylene flange and lawn mover wheel to create a train
drive wheel.
The wheel connects to
the D shaped axel via an allen
screw. Pulleys and D axels can be
bought on line from McMaster Carr (see parts list).
Original engine construction tips:
In my original train, the coal car
was the motor drive pushing the passive engine . The passive engine uses the same 2 truck
design as caboose; the 2 large white drive wheels are for show and do not
contact the tracks. The motor
driven drive wheels are in the rear truck of the coal car above. This Òdrive truckÓ uses 6 inch lawn
mower wheels instead of roller skate wheels. These ÒdriveÓ wheels have to be solidly
attached to axels via wheel hubs, with axels supported and attached to the
truck frame by wheel bearings. I could not find inexpensive wheel
hubs for ½ inch axels, so I constructed them from inexpensive zinc
pulleys. The pulley also allows
driving a second axel using a pulley belt as shown below (4 wheel drive). The pulley has an allen set screw that can grab the
axel. A Òdrive train wheelÓ can be
created by drilling through the relatively soft zinc pulley, and bolting a 7
inch diameter polyprophyline disc flange and lawn mower replacement wheel to the
pulley. With 8 inch wide tracks,
there is precious enough space to fit the motor. Note that the 500 watt, 36 volt razor scooter motor I used was discontinued. Many replacements exist (see parts
list). However, make sure the motor
you choose fits in this confined space; and is less
than dimension E. I now use 24
volt, 250 to 500 watt motors.
This drive truck mounts under the
decking of the rear of the Òcoal carÓ shown in the picture above. The coal car is filled with weights (3,
12 V heavy lead acid batteries, plus cinder blocks) for traction. Without a lot of weight, the traction
wheels will slip. This problem does not exist in the Ònew
engineÓ design, where the adult driving the engine sits over the drive wheels
to provide traction; shown later in this document.
Dimensions: a = 3.5 in. b= 9.75 in. e= 4.5 in. c=v belt tension pulley (1.5 in
diameter)
Crank engine and Thomas Ònew motor engineÓ
design construction tips
Compared to my original engine, this
design uses a wider platform that is big enough for adults to sit on. It also places the chain drives in the
center away from little fingers (original design has chain somewhat
exposed). The weight of an
adult driver, sitting over the drive wheels, eliminates the need for adding
weight for traction. Because the 6
inch wheels are rated for only 35-50 lbs each, I used
6 wheels to support me, the car and batteries (I weigh 200 lbs). The middle passive wheels can be
eliminated if you are a lighter weight adult.
To make a
hand crank engine, cut down a bike to preserve the pedal and crank gear, and
back bike wheel supports. Mount
this on the deck so that the back wheel supports are bolted to a 2 by 4 block
of wood to allow movement to adjust the chain tension.
Dimensions: a=10.25 inches inner width, b= distance between drive wheel axels 16
inches
c= length of 2 by 4 frame 34
inches d= distance between flanges is 6 7/8
inches
The new
engine uses the same wheel and axel design as the ÒoriginalÓ engine. However, the 12 inch long axels are
supported by the McMaster Carr wheel bearing on the outside of the wheels,
rather than between the wheels (shown in the next picture). Note in the picture
below, a crank car was converted to a motorized engine.
The same
McMaster Carr wheel bearings as in the original engine were used, now mounted
below the wood frame skeleton. The motor used here is a 350 watt, 24 volt gear
reduced motor for standard, no. 40 bike chain (see parts list). The box between my legs in the
photos above house the 2, 12 volt batteries, and motor
controller and throttle.
Details of
the design and dimensions are shown in the next several pictures. Note the zinc pulleys are used both as
wheel hubs (connection to axel), and to drive the back axel via a 35 inch V
pulley belt. The wheel
bearings can mount to the wood frame with some movement, to enable tensioning
the pulley belt. I would buy a 34
inch, and 36 inch belt, just in case, or design in a pulley belt tensioning as
in my original engine design (point C).
The middle wheel is non
flanged and passive, lag bolted to the frame with a ½ inch diameter lag
bolt, and used for extra weight support.
(optional).
Numbers are
used on some figures to label parts.
Parts 1-9 are superimposed
on pictures; these and more are listed on a parts list, including cost,
supplier and web address at end of document)
Upside down
side view
Dimension:
a= 34 in b=
16 in. c= 3.5 in d=
5 in
dimensions: a =34 in b= 13 in c= 6.75 e= 6 in, but adjust block that holds lag
bolted, non flanged middle wheels directly over the track rail (optional
unless needed for heavy weight riders).
Note that
this motor also comes with a flat mount making it easy to attach to the front
of the wood frame. A slot at e was
cut to allow clearance for the chain. The final engine cover should
completely cover the chain drive mechanism for safety. A wood shim can be placed under the motor
mount to adjust chain tension if necessary (not done in the picture below).
The motor
used is a 350 watt, 25 volt, gear reduced electric bike
conversion motor designed for standard bike #40 chain.
Note that
the 12 inch long, D shaped axel is ½ inch in diameter. The free wheel gear was designed for a
15 mm axel, and has a 15mm bore. I used a cooper pipe fitting at the blue
arrow (part 8) as a spacer to upsize ½ to 15 mm (approx..) The
picture below also shows details of drive wheel construction. A 4 inch zinc V pulley is attached via 4
bolts (red arrow show one) through the 1/8 inch, 7 inch diameter flange disc to
the 6 inch lawn mower replacement wheel.
An set screw on the pulley engages the D flat
surface of the axel (not shown).
The free wheel gear has 2 set screws to engage the axel.
A Thomas the tank engine body is connected to the top of the new motor drive frame.
Parts list, approx.. cost, suppliers and web links to suppliers
7. Sunlite easy off freewheel 24 tooth cost $8-20 dollars (note all costs are approx..)Source: http://www.amazon.com/Sunlite-Easy-Off-Single-Freewheel/dp/B00ZDT9E6O/ref=pd_sim_468_4?ie=UTF8&dpID=519w6F0a-4L&dpSrc=sims&preST=_AC_UL160_SR160%2C160_&refRID=15HD4NY23E5M29RJNX5V
7. Sunlite trike free wheel adapter (you need both freewheel and adapter) cost $13
Source: http://www.amazon.com/Sunlite-Trike-Freewheel-Adapter-Screws/dp/B000AO7H84
3. Low profile wheel bearing from McMaster Carr cost $10 each
Source: http://www.mcmaster.com/#standard-mounted-bearings/=11h8my1
6. D axel ½ inch diameter, 1 foot length, from McMaster Carr, cost $10
Source: http://www.mcmaster.com/#rotary-shafts/=11h8ob7
8. NIBCO 5/8" x 1/2" FTG x C Copper Fitting Reducer 600-2 $1.50
http://www.supply.com/nibco-5-8-in-x-1-2-in-ftg-x-c-copper-fitting-reducer-600-2/p487788
5. Zinc 4 or 4.5 inch V pulleys from McMaster Carr, cost $12
Source: http://www.mcmaster.com/#rotary-shafts/=11h8ob7
5. V belts: from McMaster Carr: length depends on particular geometry of your motor, axel wheel setup; 35 inches for my new engine design
Source: http://www.mcmaster.com/#v-belts/=11h98zy
Cost approx.: $8-15 dollars, depends on length.
e. (old engine) V belt tensioner: use a small, 1.5 inch Zinc pulley cost $5
http://www.mcmaster.com/#die-cast-zinc-pulleys/=11h9f3m
2 and 4. 1/8 for small wheels or 3/16 inch for large wheels; polypropropylene sheet for flange wheels; 24 by 48 inches from United States Plastics corp: cost $14
(material to cut circular disc wheel flanges)
2. Metal 6 inch lawn mower replacement wheels (rated at 50 lbs), cost approx. $6 each
Source: http://www.mcmaster.com/#lawn-mower-wheels/=11h8tkw
2. Plastic 6 inch ÒArnoldÓ lawn mower replacement wheels (easier to drill through, but rated at 35 lbs each) Cost $6-8
1. Roller skate replacement wheels and bearings for passive cars, approx. cost $40 for 8 wheels
Electric motor for new engine and crank car (uses #40 bike chain), cost $65
24 Volt 350 Watt MY1016Z3 Gear Reduction Electric Motor with 9 Tooth 1/8" Bicycle Chain Sprocket
The Electric motor that I used for the old, original engine is discontinued. Make sure you look
At the physical dimensions to make sure it will fit in the tighter constraints of the old engine design.
There are many options for 24-36 V, 350-500 watt, no. 25 chain scooter motors available from monster scooters, at website below
http://www.monsterscooterparts.com/trsc/rec-categories/motors1
motor speed constrollers: approx. cost $30-50 but depends on the motor watts and voltage you choose. Monster scooter sells motor kits with controllers at the link below:
http://www.monsterscooterparts.com/trsc/rec-categories/moto
9. Chain sprockets
and chain sizing and link sections and tools:
Please note that the 80 toothed, #25 mm sprocket used in the old, original engine is also discontinued. You can find
Sprockets at : http://www.monsterscooterparts.com/trsc/rec-categories/sprockets1
#25 Chain at : http://www.monsterscooterparts.com/trsc/rec-categories/chains
#40 bike chain: from local bike store or anywhere on the net, including amazon.com
Chain link tool to adjust size of bike chain: Topeak 2011 Update Universal Chain Tool: cost $14 http://www.amazon.com/Topeak-2011-Update-Universal-Chain/dp/B005EP95ZC/ref=sr_1_1?ie=UTF8&qid=1457622651&sr=8-1&keywords=bike+chain+cutter
chain link: KMC MISSING LINK II Bicycle Chain Link (7 and 8-Speed, 6-Pairs) cost $7 source: http://www.amazon.com/KMC-MISSING-Bicycle-8-Speed-6-Pairs/dp/B00K7YIVGE/ref=pd_sim_468_4?ie=UTF8&dpID=410qcocQBFL&dpSrc=sims&preST=_AC_UL160_SR160%2C160_&refRID=156W5RYQWC22Q6VCZWWH
chain tensioners (cost $7-10):
http://www.monsterscooterparts.com/trsc/rec-categories/chain-tensioners
Hardware: because the train car frame and trucks are made of wood, most attachments including wheels, mounted wheel bearings, etc. are usually connected using appropriate diameter and length lag bolts with appropriate spacing and lock washers. Wheel, flange, V pulley assemblies use appropriate length no 6 screw bolts, lock and spacing washers, and nuts.
I connect small roller skate wheels to wooden trucks using 5/16 by 3 inch long lag bolts. I use ½ inch by 4 inch long lag bolts for larger wheels (middle wheel of new engine), and truck pivot connection to car decks.