David Nelson's Web Site






Steam Ferry Trillium

The Trillium is a very unique and historic ferry that was built in Toronto in 1910 by Polson Iron Works and used to carry passengers between the city of Toronto and the Toronto Islands.  She was decommissioned in 1957 then restored to operating condition in 1974.  Today she continues to operate as part of the Toronto ferry fleet and usually runs on weekends when passenger volumes are high.

Trillium clip wide.jpg

The Trillium is 150 feet long, has a molded breadth of 30 feet, an extreme breadth of 47 feet and depth of 8 feet.  She was designed to carry 1450 passengers.  This was reduced to 955 later. She was powered by a double compound steam engine which had a stroke of 48", the high pressure cylinder had a 17.5" bore and the low pressure cylinder a bore of 34".

The model

December 22, 2019

The model will be built at a scale of 1:48 which will give it dimensions of 37.25" long, 11.5" wide at it's extreme and 2" deep.  The engine will have a stroke of 1.25", the bore of the high pressure cylinder will be 0.36" and the low pressure cylinder 0.71".  My plan is the have the engine operate on compressed air using the same valves and links as is used on the full size vessel.

I considered the paddle wheels to be the most complex and demanding part of the model so decided to start there.  This took three months to complete.

These paddle wheels are feathered which means the paddle boards do not follow the curvature of the wheel.  They are near vertical when they enter the water then pivot so that they are vertical as they travel through the water.  The round arms you see on the facing side of the wheel pictured above are what causes the boards to pivot back and forth.

To make all of this happen it required 98 pieces of metal, 8 paddle boards, 128 0.040" diameter bolts with nuts and 230 0.022" diameter rivets on each of the wheels.


July 9, 2020

Since completing the paddle wheel My focus has been on the cylinders, the crank shaft and their support beams.

Profile view of the cylinders, support beams and crank shaft.

The cylinders are turned from brass rod and lined with cast iron sleeves.  Pistons are turned in
aluminum.  They will each have two cast iron rings. The crank shaft is one piece turned from
12L14 alloy steel.


View of the cylinders, support beams and crankshaft looking aft. 

The arms hanging down from the crank are driven by eccentrics on the
crank.  They will be connected to the reversing mechanism which will
drive the shaft controlling the valves which manage steam entering and
 exiting the cylinders.

This is a compound engine.  High pressure steam from the boiler enters
the smaller, high pressure, cylinder seen here on the right.  Exhaust steam
from the high pressure cylinder becomes input to the larger, low pressure, 
cylinder seen on the left.  The steam entering the low pressure cylinder has
lost some of it's energy and pressure driving the high pressure piston. 
This requires the low pressure cylinder to be larger in order it to deliver
meaningful force.

December 7, 2020

Here we see the reversing gear.  When the reversing gear is in it's lower position, as seen here, the eccentric arm,
 in this case the upper turnbuckle, is driven back and forth by the eccentric on the crank shaft. This drives the
reversing gear which is connected to the shaft running through the yellow block. This shaft moves the valve to
let exhaust steam out of the cylinder then high pressure air in to drive the piston.

If the reversing gear of moved up it will be driven by the lower eccentric arm which is 180 degrees out of phase
from the upper arm.  This change in phase changes the timing of the valve such that the engine will run in the
opposite direction.

The position of the reversing gear is controlled by a lever on the operators platform.


There are 40 benches on the Trillium for passengers to sit on during the crossing.  For the model I had a friend
and fellow model builder cast the bench supports in resin.  I put the supports into a jig that holds them in
position then glue the wood slats onto the supports with fast curing super glue.  There are 250 feet of these
slats required to make the full number of benches.


The two pipes facing you are the exhaust tubes.  They will be vented down through the ferry's hull into the
base the model is sitting on.

The pipe on the right, partially hidden by the exhaust tube, is the input of high pressure air to the cylinders.
 The throttle will be connected to this pipe and a pipe from the high pressure air compressor will be connected
 to the other side of the throttle.

The ladder laying on the deck will, when installed, provide crew access to and from the hold and this deck.

The stained wood ramps on each side of the crank shaft provide safe passage for passengers over the drive shaft.


These levers are used by the ferry's engineer to control the engines.  Their functions from left to right are:

  1. Opens a valve to drain water from the low pressure cylinder.  Steam condenses a bit during operation
    which forms water in the cylinder.  Water cannot be compressed so must be drained off.
  2. Emergency shutdown.
  3. Forward/Reverse.
  4. High pressure bypass.  Used to direct steam to the low pressure cylinder if high pressure cylinder is at
    dead center at start up.
  5. Throttle.
  6. High pressure cylinder drain.


June 10, 2021

Profile of the main deck of the model.  All of the windows are glazed with acrylic.


Here we see the bow which is identical to the stern so the ferry can go back and forth to the islands without
having to turn around.  The ramp at the left would be lowered onto the dock after the ferry has come to rest
so passengers could exit and enter.  The doors at the front of the cabin slide on the black rack which allows
them to be opened and closed.


This is the operators area.  The levers control the the flow of steam and the engines.  The dials to the right of
the levers provide communication between the captain in one of the wheel houses and the operator.


These stairs provide passenger access between the main and middle decks.  The benches shown here are not
the complete set.  I have to make more benches.


A broader view of the operator's area.

 View of the pressure and vacuum gauges used by the operator to monitor the status of the system.


August 13, 2021

This model of the Trillium is now complete.  The pictures and information below describe it as complete.  For
a complete history of the project go to the top of this page and follow the updates.


Profile of the model mounted on it's base.  Note the two wheel houses.  This ferry sailed back and forth between
Toronto Harbor and the Toronto Islands without having to turn around.   The bow and stern are identical.


Ladder providing crew access to the upper deck and wheel houses.  The upper deck is for crew only.


The Trillium logo.


View of the middle deck.  Here we can see the passenger benches and stairs from the main deck.


Another view of the middle deck showing benches and the smoke stack.


The smoke stack extending above the upper deck and the air intake cowls.


Here we see the life boats suspended from their davits.  The lights on the railing are navigation lights to indicate
port and starboard when sailing at night.


The Canadian Flag flies over the wheel house.  The Trillium was originally built in 1910 but the model was built
 to reflect how the ferry looked after her restoration in 1974 which is why the red maple leaf flag was used.  The
City of Toronto flag flies on the pole behind the other wheel house.

Note the ship's bell on the roof of the wheel house.


The safety netting around the middle deck railing.


View of one end of the ferry.  The other end is identical.


The ramp used to load and unload passengers.



The links below will take you to videos of the engines and paddle wheels running.  Once they stop you can
rerun them by clicking on the video. 

The brass units running parallel to the piston rods are part of the Stevenson Reversing Gear which, controlled
by the operator, can put the engines in forward, neutral or reverse.

The paddle wheels are feathered which means the paddle boards will be near vertical when they enter the
water and remain so as they travel through the water to propel the ferry.  In a non-feathered wheel the boards
would be horizontal when they enter the water creating a lot of resistance for the engines to overcome.  You
can see this feathering action in the video.

Engines running

Paddle wheels running