The EMD F40PH is a four-axle 3,000–3,200 hp (2.2–2.4 MW) B-B diesel-electric locomotive built by General Motors Electro-Motive Division in several variants from 1975 to 1992. Intended for use on Amtrak 's short-haul passenger routes, it became the backbone of Amtrak's diesel fleet after the failure of the EMD SDP40F .

For most of their careers, Amtrak F40PH's carried their airhorns in a notch above the windshield. Some time around 1995, in the interest of reducing the noise level in the cab, the carrier began relocating the horns to a spot back on the carbody between …

Many Amtrak F40PH's had horns with these screens. Three photos and horns at left courtesy Brent Lee. As an attention-getter, the K5LA is effective almost to a fault. The horn is quite loud, to the point that residents along many commuter corridors have complained about the horns lifting them out of bed at night.

To reduce the cab noise on the already noisy F40PH, Amtrak began relocating the horns as shown in the photo at left in the early 1990's. The new location gets the horn away from the cab, but the position immediately behind the exhaust stack is less than ideal for the horn.

The F40PH locomotive, which pulled Amtrak trains for almost 30 years, used the Nathan P1234A5 on the first order, and the Nathan KL5A horn on subsequent models. The unique “boat horn” sound of Amtrak E60 electric locomotives was produced by the Nathan model P01235.

The P5a was used on Amtrak's P30CH locomotives, the turbo trains, and the first order of F40PH's (200-229) before it, in turn, was displaced by the K5LA. Amtrak 229, the last Amtrak F40PH delivered new with a P5a, models a horn with optional screen cones to keep insects and foreign matter out.

Most should have 2 horns. One is a Nathan K3H (these were the original horns installed at the factory), and the other is a K5C iirc (which was added later on to function as an “emergency horn”). IMO the K3H sounds way better than the K5C.

The Phase 1 units were also the only F40PHs to be specified with Nathan P1234a5 (P5A) horns. The horns were slightly recessed to meet clearance envelopes in the Northeast, resulting in an appropriately-sized notch in the cab roof (3) .

They were designed with a "horn notch" above the windshield just wide enough to accommodate the then-standard P5a airhorn. Amtrak's second order of F40's came with wider horn notches holding K5LA horns, horns that became and continue to be Amtrak's standard.

2006年10月28日 · BTW: For modelers that own the older Bachmann HO F40s equipped with the cheesy looking horns, Details West makes a very nice K5LA horn cluster specifically for the Amtrak F40PH. All 5 horns face forward which is correct for the prototype