The illustration shows two diagonal brushes with inward-extending shafts and bearings connected to a simplified car frame, following the arrangement in Hickley’s US551209A, figures 1 and 2. Mounting positions are schematic; the patent’s guards, spring loading and detailed rail contact are omitted. The top view and separate axial end views show the same brush phase. Brush diameter is proportional in the drawing, while the overall assembly is not a dimensioned reconstruction.
This page illustrates a paired-brush railway track-cleaner described in an 1895 patent. Two separate diagonal brushes cross the two rails. The calculator gives nominal tip speed from entered diameter and RPM, then resolves a representative in-plane tip velocity using the angle from the transverse direction.
Street Railway Sweeping Car Interactive Calculator
Explore nominal tip speed and geometric velocity components for paired diagonal rail brushes. Each brush crosses one rail, and its entered axis angle is measured from the transverse datum. Actual friction-driven RPM is not predicted.
Equation Used
- Two separate cylindrical brushes are shown. Each crosses its respective rail diagonally, following the arrangement described in U.S. Patent 551,209.
- The entered angle is measured from the transverse horizontal datum. The representative in-plane normal vector has lateral magnitude v sin(theta) and along-track magnitude v cos(theta).
- The paired brushes rotate in opposite senses so each moves outward at its rail; both end faces of any one rigid brush share the same signed rotation.
- The patent describes frictional drive from car motion, but vehicle speed, slip and the resulting brush RPM are not solved; RPM remains a user input.
- Bristle flexibility, rail profile, debris properties, contact force, torque, power, wear, structural load and cleaning efficiency are not predicted.
Compare tip speed and its geometric components for the two rail brushes. The calculation does not predict wear, debris motion or cleaning performance.
How the paired rail brushes work
Hickley’s 1895 track-cleaner places a separate cylindrical brush diagonally across each rail. The axles extend inward toward supports attached to the car. Figures 1 and 2 show the paired layout in plan and elevation; the specification describes outward rotation produced by frictional contact as the car moves. This is the historical arrangement used for this teaching illustration, not a reconstruction of every type of sweeping car.
The gold cylinders show the brushes from above. Their visible longitudinal rows move as projected points on a rotating cylinder. The axial end views below show the same phases, both viewed along a shaft direction toward the right of the plan. The illustrated lower surface moves outward at each rail; slip and contact forces are not calculated. The dashed horizontal lines are transverse datums: zero degrees means the brush axis is perpendicular to the track direction.
The grey frame and bearings are simplified supports. Guards, vertical adjustment, springs, rail profile and bristle deflection are omitted. Brush diameter scales proportionally; brush length, rail spacing and mount sizes are illustrative.
What this calculator can show
Use the model to explore how entered brush diameter and RPM change nominal tip speed, and how the selected angle resolves that speed into lateral and along-track components. It is suitable for understanding the kinematics of this paired-brush arrangement.
The results do not size a motor, establish a safe RPM, prescribe bristle preload or predict snow removal. The patent describes frictional drive, while this calculator takes RPM as an independent input; it does not solve vehicle speed or slip.
Speed and its components
For diameter D in metres and rotation rate N in revolutions per minute, nominal tip speed is v = πDN/60. Frequency is f = N/60.
At the representative in-plane tip position, a velocity normal to a brush axis inclined by θ from transverse has component magnitudes |v lateral| = v sin θ and |v along track| = v cos θ. Their vector magnitude is v. The vector key illustrates this geometric decomposition; it is not a material-ejection trajectory or the instantaneous velocity of every visible row.
Worked example
Enter a 600 mm diameter, 200 RPM and a 20° angle from transverse. Converting diameter gives D = 0.6 m.
Tip speed is π × 0.6 × 200 / 60 = 6.28 m/s. The lateral component is 6.28 sin 20° = 2.15 m/s, the along-track component is 6.28 cos 20° = 5.90 m/s, and frequency is 200 / 60 = 3.33 rev/s.
These are geometric speed values. They do not specify a suitable operating condition or a debris throw distance.
Model limits
Increasing diameter or RPM increases all calculated speed magnitudes. Increasing the angle in the available range increases the lateral component and decreases the along-track component. At zero angle, the lateral component is zero and the diagram omits its arrow.
Actual cleaning depends on bristle properties, contact, loading, slip and material conditions that are not entered. This page provides no wear-life, material-selection, electrical-current, preload or cleaning-efficiency recommendations.
Frequently asked questions
What is the angle measured from?
The transverse direction, perpendicular to the rails. Zero degrees places the brush axis across the track; it is not an angle measured from the direction of travel.
Does the calculator predict how far debris is thrown?
No. It calculates nominal brush tip speed and geometric component magnitudes. Debris contact and trajectories are not modeled.
Why is RPM entered separately?
The referenced patent describes friction-driven rotation. This calculator does not solve the vehicle-speed, contact and slip relationship, so brush RPM is an independent input.
Do the top view and end views show the same motion?
Yes. Each end view uses the same signed brush phase as its corresponding projected surface rows. Playback is deliberately slowed for visibility.
Does this model provide motor power or brush settings?
No. Torque, motor power, preload, wear and cleaning performance require information absent from this model.
References
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