Rail, Transit & Rolling Stock Manufacturing worked example

Transit Fleet Spares Forecast at 99% spares line uptime: a worked example

What does the result look like when spares line uptime reaches 99%? The full calculation is worked below with real intermediate numbers. Use it when transit fleet spares forecast in rail, transit and rolling stock manufacturing is being asked to take on more work and you need to know if there is room.

The inputs for this scenario

  • Spare units produced per production cycle: 4 units / cycle (unchanged)
  • Spares production cycles available: 480 cycles (unchanged)
  • Spares line uptime: 99 % (raised for this scenario; the documented default is 90)
  • First-pass yield on spare parts: 97 % (unchanged)

Working through the calculation

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

How this compares with the baseline

  • Against the tool's baseline example, where spares line uptime sits at 90% and the headline result is 1,676 units, this scenario comes in 10% above the baseline at 1,844 units.
  • A figure at this level is achievable when spares line uptime is genuinely sustained, not just peaked for a shift. It models one part family at a time with a single yield; a spares kit spanning many different parts needs a separate run per part.

Results at a glance

  • Good transit fleet spares forecast capacity: 1,844 units (headline result)
  • Gross transit fleet spares forecast capacity: 1,920 units
  • Transit fleet spares forecast downtime loss: 19.2 units
  • Transit fleet spares forecast yield loss: 57.02 units

Run it with your numbers

  • Every input above is editable in the live Transit Fleet Spares Forecast calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.