Why does yield apply after uptime, not to gross output?

Because a bogie rejected during a stop was never built. Applying yield to post-uptime output keeps the loss consecutive, so good bogies stay within the parts the line actually started.

Should the required bogies include spares or scrap?

Add any extra bogies the period must deliver to the required count, because the calculator compares good output with that total. Spares, warranty replacements and scrap allowances are all valid demand on the line.

What uptime figure should I enter?

Use a period average from the line's own records, including changeovers, breaks and breakdowns. A figure from a good week overstates capacity, and the shortfall then appears as overtime rather than as a wrong calculation.

Can this compare two lines making different bogie types?

Only when bogies per cycle and cycle counts describe the same work content. For a mixed line, run each type separately or enter a weighted bogies per cycle and keep the yield specific to the mix.

Rail, Transit & Rolling Stock Manufacturing calculator

Bogie Assembly Throughput Calculator

Turn assembly cycles and bogies per cycle into gross capacity, then take downtime and yield losses out to get the good bogies the line really delivers. The result is compared with the bogies your period requires.

What this calculator does

Good bogies per period from cycle output, uptime and first-pass yield, compared with the bogies the period requires.

Formula used

Gross bogies = bogies per cycle × available assembly cycles
Downtime loss = gross bogies × (1 − uptime ÷ 100)
Yield loss = (gross bogies − downtime loss) × (1 − yield ÷ 100)
Good bogies = gross bogies − downtime loss − yield loss
Capacity versus demand = good bogies ÷ required bogies × 100

Inputs explained

Bogies per Assembly Cycle: Bogies completed in one assembly cycle.
Available Assembly Cycles: Assembly cycles available in the period.
Bogie Line Uptime: Share of available cycles the line actually runs.
First-Pass Yield: Share of started bogies that pass first time.
Required Bogies in the Period: Bogies the period must deliver.

How to use the result

Best suited to sizing a bogie line against a build plan, testing how downtime or yield shifts capacity.
The model assumes bogies per cycle is stable; a mixed build changes it. Uptime and yield are entered as single period averages, not per-shift values.

Current U.S. benchmarks

Steel mill PPI stands at 381.162 (BLS, Aug 2026), up 23.4% from a year earlier. New factory orders are up 8.5% year over year (Census).
The U.S. has 11,691 transportation equipment establishments employing about 1,682,910 workers (Census County Business Patterns, 2023).

Common questions

Why does yield apply after uptime, not to gross output? Because a bogie rejected during a stop was never built. Applying yield to post-uptime output keeps the loss consecutive, so good bogies stay within the parts the line actually started.
Should the required bogies include spares or scrap? Add any extra bogies the period must deliver to the required count, because the calculator compares good output with that total. Spares, warranty replacements and scrap allowances are all valid demand on the line.
What uptime figure should I enter? Use a period average from the line's own records, including changeovers, breaks and breakdowns. A figure from a good week overstates capacity, and the shortfall then appears as overtime rather than as a wrong calculation.
Can this compare two lines making different bogie types? Only when bogies per cycle and cycle counts describe the same work content. For a mixed line, run each type separately or enter a weighted bogies per cycle and keep the yield specific to the mix.

Last reviewed 2026-10-01.