Evolution of Tubular Rail

The Tubular Rail concept developed from the observation of the relationship between the balance point of a beam at rest on two points. The inventor noted when sliding a pencil off the edge of a desk, given a uniform weight distribution, the pencil - or any beam - could be pushed to almost 50% of its length before tilting would occur.

That simple observation, and the considerable research that followed, convinced TRI founder, Robert Pulliam , that there is a huge market for a solution that provides an efficient, safe, and low polluting form of transportation - but only if costs could be slashed. Tubular Rail is that low-cost, low-impact solution.

Working together with engineers and engineering institutions, the inventor refined and enhanced the design of the Tubular Rail Technology. Graduate students at the Thayer School of Engineering at Dartmouth College (“ Dartmouth ”) have provided financial and engineering analyses. A first report and analysis was issued in early March, 2006, and a second report on the design of the passenger car in March, 2007. These were followed by a third report issued in March of 2008 on power and propulsion. The Texas Transportation Institute ("TTI") at Texas A&M University has presented a proposal for further feasibility and engineering studies to be conducted jointly by the prestigious Southwest Research Institute® ("SwRI") and TTI.

How Is Tubular Rail a Revolutionary Train?

Tubular Rail Technology utilizes essential railroad components. In a traditional train, the following components are employed:

• Steel wheel running on a steel rail (this produces a low co-efficient of friction and a very economical method of transportation).
• Railroad bridges (devices to span open space where it is not possible to have a continuous roadbed). A bridge must carry its own weight and that of the train.
• The roadbed (an accumulation of mass that holds the tracks in place and distributes the forces generated by the passing train).
• Propulsion (provided by a locomotive or motor contained within cars).
• Passenger cars (the compartment for safely transporting passengers).

Tubular Rail Technology maintains the same five characteristics of rail transportation but reconfigures them in a highly innovative fashion. The Tubular Rail Technology employs the following features:

• The functionality of the bridge and passenger car is combined. This is accomplished by reversing the orientation of the wheel and the rail. By placing the wheel (or roller) permanently on a fixed structure and the rail on the now strengthened car, the car itself bridges the space between the rollers.
• Tubular Rail Technology uses the principle of the cantilever beam - a projection anchored at one end. Since the car is moving within- and is held by - the support rings (stanchions), the effect is to create a cantilever beam. The beam is fixed in its vertical orientation but mobile in its horizontal orientation. Therefore this rolling cylinder is constantly shifting from a cantilever beam on the ends to a post and beam (in its middle) and then back again.

Questions

 How does the Tubular Rail car turn?

Lateral change in direction---is made by a combination of two forces.  They are rotation of the roller from the perpendicular to direction of travel axis. They may also be taken out of the horizontal plane thus producing a super elevation effect.  In other words, if in straight travel the axis of movement is thought of as a line perpendicular to the axis of the rollers, a turn is initiated when the car encounters a set of rollers not perpendicular to the travel axis and the car will tend to move to that side on which the acute angle is found.  The second influence is that of the side roller on the obtuse side of the next encountered side roller.  The curved portion of the side rail contacts this roller and the car is forced to its realignment.  The effect of this change on the passenger is mitigated by several design elements that can be varied; they are speed of the vehicle, spacing of the side rollers and the elliptical radius of the rails at the front and rear of the vehicle. Increasing the radius alters the time duration of load transfer to the roller.

 How many passengers will the Tubular Rail car carry?

The design of the Tubular Rail car creates a usable passenger floor space of nearly 3000 square feet. This allows a seating capacity of 400 to 500 passengers without crowding and allowance for food service and restrooms.

 What are the speed targets?

In order to obtain a significant market share by inducing modal shift from automobiles and short haul air routes, the Tubular Rail system must be capable of traveling at speeds in the vicinity of 150 mph for the 100 to 600 mile trips.  As a rule of thumb modal shift occurs if the automobile trip time can be cut in half the air trip is not exceeded by a factor of two.  At these speeds the impact of aerodynamic forces is the major determinant of energy use, not rolling friction.

 For shorter trips convenience and location is a major determinant of rider ship.  These are the commuter and light rail markets.  Speed, while still important is not the critical factor and thus a slightly different car form is used with less critical attention paid to the aerodynamic profile.  The more rectangular cars will operate at speeds up to 90 mph.

 What is the power source?

The power is provided though electrically driven AC motors.

 What is the maximum grade?

For most passenger trains other than Maglev, maximum grade is limited to 2 or even 3 percent.  Maglev, with its propulsion in the guide way claims to be able to make up to a 10 per cent grade.  Like Maglev, Tubular Rail vehicle are propelled by external drive and thus the power available can be matched to need without increasing the onboard mass of the vehicle.  In rail systems with onboard drive an increased grade capability would require this additional mass to be accelerated whenever the train accelerates no matter what the grade. 

 The characteristics of the Tubular Rail approach means that grades greater than current wheel on rail systems can be considered but that the transition curve to these greater grades will be a gentle constant change.  The off shoot of this approach is a higher  quality ride for the passenger.

 How does the Tubular Rail car stop?

The braking system (non emergency) of the Tubular Rail system will rely on the creation of friction between the braking device and the resistance plate on the column.  However most routine braking is done by controlling the speed at which the rollers are rotating and when coming into a station the rollers actually serve to regenerate energy back to the grid.

 What about emergency evacuation?

Vehicles will be equipped with a variety of readily available equipment to facilitate an evacuation including those passengers with physical limitations.  The nature of the vehicles allows for ample space to store inflatable slides, ladders and slings to lower people to the ground.  Additionally at least on column of the three supporting the vehicle at any one time may be equipped with a permanent access ladder.

 Will the Tubular Rail car be ADA (American with Disabilities Act) compliant?

Yes, level floor boarding and extra wide aisles will allow those in wheel chairs to fully access the full car length  Stations will need to be accessible as well with ramps and or elevators.. 

 How are system costs keep down?

Tubular Rail estimates that 70% of total system costs are related to the components that are both standardized and mass produced.  It is only the footer and electrical installation that is site specific.  Since the system is essentially 95% air space there is simply less material involved.  Another key aspect is the difference in compensation to the land owner where Eminent Domain is required.  Compensation for easement is lower than Right of Way because the landowner retains some use of the land.   

Why is a new form of transportation needed?

One thing Tubular Rail does not advocate is the removal of existing systems such as light or commuter rail and that the highway system and urban streets should remain, for the most part, as they are.  However it is clear that dependence on the automobile has high costs associated with it and that these costs (environmental, dependence on imported oil, congestion issues and construction and maintenance of highways) are rising.  Traditional rail options solve some of these issues but capital costs associated with “new” rail, commuter or light, come with staggering price tags. 

Tubular rail seeks to keep the best of rail, safety and efficiency, while addressing the difficulty of funding and building systems to obtain the benefits that rail offers.