How do you calculate relay test capacity?

Multiply output per cycle by available cycles for gross capacity, then multiply by uptime and first-pass yield. Here 4 × 480 = 1,920 gross, and 1,920 × 0.90 × 0.97 = 1,676 good units.

What is the difference between gross and good capacity?

Gross capacity assumes a perfect bench with no downtime and no failures. Good capacity, 1,676 units in the default, is what you can actually deliver after losing 192 to downtime and 52 to yield.

What is a good first-pass yield for relay testing?

Well-controlled relay lines run 95-99% first-pass. The 97% default is solid; sustained yield below about 90% usually points to a process or incoming-quality issue.

How much capacity does downtime cost me?

With 90% uptime you lose 10% of gross — 192 units in the example. Raising uptime is often cheaper capacity than adding a second bench.

Should I add a second test bench?

Compare good capacity to demand. If demand exceeds 1,676 units and uptime and yield are already high, added benches or shifts are justified before you can raise them further.

Why multiply uptime and yield instead of subtracting?

They are sequential losses: yield acts on the units the bench actually ran during its uptime, so the losses compound multiplicatively rather than adding up.

Rail Signaling & Wayside Equipment calculator

Relay Test Capacity Calculator

Relay Test Capacity estimates how many signaling relays your test bench can actually deliver good, first-pass, in a given period once you account for bench uptime and first-pass yield. Test engineers and production planners in rail signaling shops use it to promise realistic throughput, spot bottlenecks, and decide when a second bench or shift is justified. The point is the gap between gross capacity and good capacity — the units you lose to downtime and to relays that fail their first test. Sizing that loss keeps commitments honest and highlights where reliability improvements pay off.

What this calculator does

Estimate relay test capacity for rail signaling and wayside equipment using production-ready inputs so teams can confirm whether capacity can cover demand before committing the schedule.
Use it when relay test capacity in rail signaling and wayside equipment is being asked to take on more work and you need to know if there is room.
It multiplies output per cycle by available cycles for gross capacity, then applies uptime and first-pass yield to get good, deliverable capacity.

Formula used

Gross relay test capacity = relay test capacity output per cycle × available relay test capacity cycles
Good relay test capacity = gross capacity × expected relay test capacity uptime × expected relay test capacity first-pass yield

Inputs explained

Relays tested per test cycle:
Available test cycles in the period:
Expected test bench uptime:
Expected relay first-pass yield:

How to use the result

Use it when planning test-bench throughput for a signaling order or evaluating whether to add bench capacity.
It treats uptime and yield as flat averages, so a bench with erratic downtime or a bad batch can miss the good-capacity figure in any single period.

Current U.S. benchmarks

Steel mill PPI stands at 348.53 (BLS, May 2026), up 6.7% from a year earlier. New factory orders are up 2.3% 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

How do you calculate relay test capacity? Multiply output per cycle by available cycles for gross capacity, then multiply by uptime and first-pass yield. Here 4 × 480 = 1,920 gross, and 1,920 × 0.90 × 0.97 = 1,676 good units.
What is the difference between gross and good capacity? Gross capacity assumes a perfect bench with no downtime and no failures. Good capacity, 1,676 units in the default, is what you can actually deliver after losing 192 to downtime and 52 to yield.
What is a good first-pass yield for relay testing? Well-controlled relay lines run 95-99% first-pass. The 97% default is solid; sustained yield below about 90% usually points to a process or incoming-quality issue.
How much capacity does downtime cost me? With 90% uptime you lose 10% of gross — 192 units in the example. Raising uptime is often cheaper capacity than adding a second bench.
Should I add a second test bench? Compare good capacity to demand. If demand exceeds 1,676 units and uptime and yield are already high, added benches or shifts are justified before you can raise them further.

Last reviewed 2026-05-12.