OSP Schedule: Railroad Permit on the Critical Path
A county government awards a project to install a 6 km, 48-fiber singlemode OSP route linking three buildings. The route includes a 90 m directional bore beneath an active freight railroad, a 1.2 km aerial section on existing poles, and 1.8 km in existing duct. The railroad permit is expected to take five weeks; the utility pole attachment approvals take three weeks. The contract allows eight weeks from notice to proceed. You have two four-person crews, one splicing trailer, and a deadline tied to a state grant that cannot be extended. The splice count is 40 closures, and acceptance requires bidirectional OTDR plus OLTS. The county wants a schedule and a contingency plan at the pre-construction meeting.
1. Identify the critical path and determine whether the eight-week contract is achievable with the stated resources.
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The railroad crossing governs. Permit approval is five weeks, then directional bore about one week, cable pull and closure placement about one week, splicing about one week, and testing/closeout about half a week. That sequence totals about 8.5 weeks, which is half a week beyond the contract and therefore has negative float. The pole approvals take three weeks and can run in parallel with the railroad permit. The aerial and duct work, about 3.0 km, can also proceed while the railroad permit is pending. The critical path is therefore permit-to-cross to bore to pull to splice to test. Without compression, the grant deadline is at risk. The plan should show the crossing as the driving activity and protect it with an expediter and a prequalified bore subcontractor.
2. Propose a mitigation plan that recovers the schedule without relying on overtime alone.
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Submit the railroad permit and pole applications on day one, and assign a permit expediter to track both. Pre-fabricate and pre-splice the aerial and duct sections while the railroad permit is pending; those sections do not depend on the crossing. Pre-stage the bore subcontractor and confirm the railroad flagger requirement so the bore starts the day the permit is issued. Run the two crews from opposite ends of the route and meet at the crossing, which levels resources and shortens the pull sequence. Pre-splice closures in the shop and use preterminated cable where the route allows. Keep overtime as a limited contingency, not the primary plan. If the permit slips past week five, request a grant extension in writing immediately and document the railroad's delay; do not wait until the final week.
3. Define the acceptance-test plan and the closeout documents you would require before final payment.
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Test every fiber bidirectionally at 1310 and 1550 nm with an OTDR, and perform OLTS insertion-loss tests on all 48 fibers. Use bidirectional averaging for splice loss, and require fusion splices at 0.1 dB or better, with any splice above 0.15 dB reworked. Confirm connector loss and ORL against the project specification. Test the railroad bore section with special attention to bend loss at the entry and exit. Closeout should include as-built route drawings with GPS coordinates, splice schematics, OTDR and OLTS files in native format, test reports, permit closeout letters, and a warranty package for the bore and cable. Final payment should be tied to county acceptance of the test data and a physical walkthrough, not merely cable placement.