UP And NS Ask FRA To Waive Cab-Signals For Big Boy 4014

Published: March 17, 2026

Union Pacific’s famed 4-8-8-4 “Big Boy” No. 4014 could see new eastern mileage on Norfolk Southern in 2026—but first, the two railroads are asking federal regulators for help bridging a technology gap between a modern signal network and a historic steam locomotive.

In a newly filed request to the Federal Railroad Administration (FRA), Union Pacific and Norfolk Southern are seeking a temporary, route-specific waiver from the federal requirement that the controlling locomotive be equipped with cab-signal apparatus when operating in cab-signal territory. The issue: Norfolk Southern still operates extensive cab-signal territory, while Big Boy 4014 is not currently equipped with cab signals and—according to NS—cannot be practically retrofitted without major, irreversible alterations to the locomotive.

The petition also points to a broader industry shift. NS notes that Union Pacific received approval to discontinue its cab-signal system in 2022, which led to decommissioning and removal of cab-signal equipment from UP locomotives, including Big Boy 4014. In place of cab-signal hardware, UP modernized 4014 to support a compliant onboard Positive Train Control (PTC) system for operation on PTC-mandated segments. UP’s position to regulators is that a waiver can maintain “equivalent or better” safety because 4014 is fully equipped with PTC, which provides real-time enforcement of authorities, speed limits, and work-zone protections.

Cab Signals

Cab signals are an in-cab display system that communicates signal aspects and (in many implementations) can enforce speed or stops, depending on the territory’s configuration. On portions of NS, cab signals are more than a “nice to have.” The railroad notes that much of its cab-signal territory does not include a complementary wayside signal system, meaning the cab signal is central to how crews receive and comply with signal indications.

Federal rules reflect that reality. 49 CFR § 236.566 requires that the locomotive from which brakes are controlled on any train operating in automatic train stop, train control, or cab-signal territory be equipped with the corresponding operative apparatus. NS’s petition explicitly seeks relief from that requirement for Big Boy-led movements during the tour.

Where Big Boy would run on NS

While Union Pacific has publicized its broader “coast-to-coast” heritage tour theme tied to America’s 250th anniversary, it has not (as of the filings) published a full, official east-of-UP route.

Norfolk Southern’s waiver petition, however, identifies multiple cab-signal line segments the 2026 Heritage Excursion Tour train is planned to traverse—spanning a corridor that would take Big Boy across major NS arteries between central Pennsylvania and northern Ohio. The filing lists cab-signal territory segments on or associated with:

Royalton Branch (Lancaster Subdivision): CP Shocks to CP Paxton
Harrisburg Line: CP Paxton to CP Harrisburg
Pittsburgh Line: CP Harrisburg westward through the Altoona territory toward Pittsburgh-area control points
Fort Wayne Line: west of Pittsburgh-area control points toward Alliance
Cleveland Line: Alliance area to a Cleveland-area drawbridge segment

NS describes the relief it seeks as time-limited and train-specific, applying only for the tour’s Big Boy-led movements over these cab-signal territories.

The petition places the tentative excursion window between May 25 and July 29, 2026, with NS committing to notify FRA of any schedule changes.

What NS is offering in exchange: layered operating restrictions

The most consequential part of the filing is the list of operational mitigations NS says it would impose to offset the absence of cab-signal equipment on the lead locomotive. Among them:

Fully functional and operative PTC (with en-route failure handled under existing rules)
Absolute block protection in advance of the train
Maximum speed not to exceed 40 mph, consistent with NS steam locomotive restrictions and more conservative than certain federal allowances for cab-signal failures under absolute block
Wayside signal compliance for interlockings/controlled points, with adherence to NS signal rules
Experienced/qualified crew (UP-qualified steam operators plus an NS-qualified pilot or train crew in the controlling locomotive for territory familiarity and rule compliance oversight)
Dispatcher/route mitigations, including ensuring the route is clear and preventing conflicting movements until the excursion clears, with restrictions on reverse moves
Incident reporting per NS protocols

NS also emphasizes it is not proposing any physical changes to its signal and train control systems—only temporary operating conditions tailored to this specific movement.

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