Tunnel Boring & Heavy Civil Equipment worked example

Torque Capacity at 99% drive availability: a worked example

Push drive availability up to 99% and the picture changes. This example computes every intermediate figure at that operating point. Use it when torque capacity in tunnel boring and heavy civil equipment is being asked to take on more work and you need to know if there is room.

The inputs for this scenario

  • Cutterhead torque delivered per rotation: 4 units / cycle (unchanged)
  • Available cutterhead rotations in the window: 480 cycles (unchanged)
  • Drive availability (uptime): 99 % (raised for this scenario; the documented default is 90)
  • First-pass boring effectiveness: 97 % (unchanged)

Working through the calculation

  • Applying the documented formula (Gross torque capacity = torque capacity output per cycle × available torque capacity cycles) to the inputs above produces each figure below.
  • At this operating point the engine returns 1,844 units for good torque capacity, the number this scenario is built around.
  • At this operating point the engine returns 1,920 units for gross torque capacity.
  • At this operating point the engine returns 19.2 units for torque capacity downtime loss.
  • At this operating point the engine returns 57.02 units for torque capacity yield loss.

How this compares with the baseline

  • Against the tool's baseline example, where drive availability sits at 90% and the headline result is 1,676 units, this scenario comes in 10% above the baseline at 1,844 units.
  • It multiplies torque delivered per rotation by available rotations to get gross capacity, then discounts it by drive uptime and first-pass boring effectiveness to yield usable capacity. The value of this scenario is the size of the gap it exposes: that gap, priced out over a year, is the budget you can justify spending to close it.

Results at a glance

  • Good torque capacity: 1,844 units (headline result)
  • Gross torque capacity: 1,920 units
  • Torque capacity downtime loss: 19.2 units
  • Torque capacity yield loss: 57.02 units

Run it with your numbers

  • Every input above is editable in the live Torque Capacity calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.