- +Genuine reconditioned Nathan P5 five-chime locomotive horn
- +Only $50 more than the 3-chime K3 544K kit
- +Heavy-duty 1NM compressor + 5-gal 8-port tank included
- +Shared-diaphragm P-series design is easier to service
- +5-year horn warranty, 2-year kit warranty
- −No published dB rating
- −5-6 s blast, shorter than the K3 kit's ~7 s
- −Kit page doesn't specify P5 bell set or casting
- −Recharge listed as both ~90 s and 2 min
- −Bulky: 30 lb horn plus 20 lb tank
Methodology
This review aggregates publicly available information from manufacturer specifications, retailer listings, and verified user reviews. We do not perform hands-on testing. For this kit we relied mainly on HornBlasters’ official HK-P5-544K product page, which publishes the kit’s specs, fill rates, contents, and warranty. We cross-checked it against HornBlasters’ standalone P5 horn and HornAir 5-gallon system listings, Nathan AirChime’s own site, and Wikipedia’s Nathan Manufacturing entry for the P-series history and chord. Every number below comes from one of the pages listed in the Sources section. Last reviewed: 10/22/2026.
Quick verdict
The Nathan AirChime P5 544K is a reconditioned five-chime locomotive horn sold together with a heavy-duty onboard air system. You get a sand-cast aluminum Nathan P5, a 1NM compressor, and a 5-gallon, 8-port tank switched between 110 and 150 PSI, which HornBlasters says is good for 5-6 seconds of continuous blast. At $2,799.99 it costs only $50 more than the three-chime K3 544K kit and about $2,200 less than the K5 544K kit, so it’s the cheapest way into a genuine five-chime Nathan setup from HornBlasters. On the downside, there’s no published dB rating, the listing doesn’t say which P5 bell set or casting generation you’ll get, and the page contradicts itself on recharge time. In our editorial opinion it earns 4.3/5.
What it is
The P5 544K (part number HK-P5-544K) is a turnkey kit built around the Nathan AirChime P5, a five-chime horn from Nathan’s P-series. According to Wikipedia’s Nathan Manufacturing entry, the P-series was refined from a Nathan truck horn for locomotive use in 1953. Its nickname is the “President’s whistle,” and the P5 itself was used on Illinois Central, Rock Island, and Southern Pacific passenger trains. The standard P5 is known for an A dominant 7th chord, which is warmer and more old-school than the B major 6th of the modern K5LA. Nathan AirChime’s own site says the company supplies over 90% of America’s locomotive horns.
Like HornBlasters’ other Nathan kits, this horn is not new. HornBlasters says its Nathan horns come from retired locomotives and are sandblasted, refinished in black powder coat, and rebuilt with new diffuser rings, diaphragms, and cushion rings. The body is sand-cast aluminum with stainless steel internals.
The “544K” part of the name is the air system: a HornBlasters 1NM Stealth Black compressor feeding a HornAir 5-gallon, 8-port tank. HornBlasters also says the setup lets you inflate tires in an emergency.
Who it’s for: truck and show-build owners who want a real locomotive horn with the vintage P-series voice and would rather buy one SKU than source a horn, tank, compressor, valve, and wiring separately. If you only want the horn, our standalone Nathan P5 review covers it in more depth. You can browse every Nathan model we cover on the Nathan reviews hub.
Specifications
| Spec | Value |
|---|---|
| Part number | HK-P5-544K |
| Horn | Nathan AirChime P5 (reconditioned, ex-locomotive) |
| Trumpet / bell count | 5 |
| Horn material | Sand-cast aluminum body, stainless steel internals, black powder coat |
| Horn dimensions (L × W × H) | 19.5 × 19.75 × 10 in |
| Horn weight | 30 lb |
| Horn air inlet | 1/2 in NPT |
| Sound output | Not published by HornBlasters for this kit |
| Chord | Standard P5: A dominant 7th (per Wikipedia; bell set not specified on the kit page) |
| Operating (cut-out) pressure | 150 PSI |
| Restart (cut-in) pressure | 110 PSI |
| Blast time | 5-6 seconds continuous per full tank |
| Compressor | HornBlasters 1NM Stealth Black, 12 V DC, 25 A max |
| Compressor duty cycle | 100% @ 100 PSI |
| Compressor flow @ 0 PSI | 1.75 CFM |
| Compressor dimensions / weight | 10.75 × 4 × 6.75 in / 10.1 lb |
| Tank | HornAir 5-gallon, 8 ports |
| Tank dimensions | 20.5 in long × 9.5 in diameter, 11.5 in tall with legs |
| Tank weight | 20 lb |
| Fill time 0–150 PSI | 6 min 45 s (±10 s) at 13.8 V |
| Refill time 110–150 PSI | 2 min (±5 s) at 13.8 V in the spec table; “about 90 seconds” in the marketing copy |
| Valve | 1/2 in Black Widow stainless steel electric air valve |
| Air line | 17 ft of 1/2 in DOT-approved line |
| Power source | Onboard air (12 V compressor + tank) |
| Price | $2,799.99 (compare-at $2,825.99; HornBlasters, checked 10/22/2026) |
| Warranty | 5 years on the horn; 2 years manufacturer’s defect on the rest of the kit |
Two notes on this table. First, HornBlasters doesn’t publish a decibel figure on the kit page, so we don’t list one. Second, the page gives two different recharge times. The marketing text says “1-minute and 30-second recharge” and “roughly 90 seconds,” while the fill-rate table says 2 minutes (±5 s) from 110 to 150 PSI at 13.8 V. We treat the measured table figure as the one to plan around.
What’s in the box
Per HornBlasters’ “Includes” list:
- Nathan AirChime P5 train horn (reconditioned)
- HornBlasters 1NM Stealth Black air compressor
- HornAir 5-gallon, 8-port air tank
- 110/150 PSI pressure switch with 40 A relay
- Remote-mountable air filter housing plus spare filter elements
- 17 ft of 1/2 in DOT-approved air line
- Black Widow 1/2 in stainless steel electric air valve kit
- Brass NPT fitting kit with safety blow-off and drain cock
- 22 ft of 8-gauge red wire, plus 22 ft each of 18-gauge blue and grey wire
- Complete wiring kit with fuse holder and fuses
- Mounting hardware and detailed instructions
Pros
- Five chimes for close to three-chime money. At $2,799.99 the kit is $50 more than the K3 544K and about $2,200 less than the K5 544K.
- Genuine Nathan P-series horn. It’s a reconditioned P5, a model Wikipedia documents in passenger and freight service, not a lookalike trumpet set.
- Easier to service design. Wikipedia notes that P-series horns share one diaphragm across the bells, which made them easier to repair than the M-series.
- Heavy-duty air system included. The 1NM compressor is rated at 100% duty cycle at 100 PSI, and the 8-port tank leaves spare ports for tire inflation.
- Strong warranty for used hardware. 5 years on the horn and 2 years on the rest of the kit.
- Detailed spec disclosure. Dimensions, weights, amperage, duty cycle, flow, and fill rates are all published.
Cons
- No published dB rating. You can’t compare loudness on paper against other kits.
- Shorter blast than the K3 kit. 5-6 seconds per tank, compared with about 7 seconds for the K3 544K on the same air system (our comparison of HornBlasters’ figures).
- Bell set isn’t specified. Wikipedia describes several P5 variants (standard, P5A, zero-bell) and notes that post-1976/78 “new cast” bells can sound discordant. The kit page doesn’t say which one ships.
- Conflicting recharge figures. The listing says both “about 90 seconds” and 2 minutes for the same refill.
- Large and heavy. The horn is 19.75 in wide and weighs 30 lb, and the tank adds another 20 lb.
- Road use is restricted. Check your state’s horn and noise rules first. See our train horn legality guide.
Alternatives
- Nathan AirChime P5 (standalone): The same horn alone for $1,999.99 from HornBlasters. Add the Heavy-Duty HornAir 5-gallon system without the tire kit (HA-544K-HK, $659.99) and you’re at about $2,660. That system already includes the wiring and brass fittings, so the kit costs roughly $140 more and adds the Black Widow valve and 17 ft of 1/2 in air line in one box.
- Nathan AirChime K3 544K Kit: A reconditioned three-chime K3LA on the same 544K air system for $2,749.99. It gives about 7 seconds of honk time and has a smaller horn, but only three notes.
- HornBlasters Admiral 544K: HornBlasters’ own five-trumpet kit on a 5-gallon air system for $999.99. It’s not railroad hardware, but it costs about a third as much.
If you want the modern five-chime chord instead, HornBlasters’ K5 544K kit with a K5LA or K5HA starts at $4,999.99. Our K5LA review and Nathan vs Leslie guide cover the differences.
Install / compatibility notes
- Find room for three large parts. The horn (19.5 × 19.75 × 10 in, 30 lb), the tank (20.5 in long, 11.5 in tall with legs, 20 lb), and the compressor (10.75 × 4 × 6.75 in, 10.1 lb) all need solid mounting points. The horn is the bulkiest piece. HornBlasters’ standalone listing says the P5’s bells are reversible, which gives you some flexibility in how it faces.
- Plan the electrical load. The compressor draws up to 25 A at 12 V DC. It’s switched through the included 40 A relay and 110/150 PSI pressure switch and fed by 8-gauge wire. Fill times are rated at 13.8 V, so expect slower fills with the engine off.
- Plumb with 1/2 in line. The horn has a 1/2 in NPT inlet, which matches the kit’s 1/2 in Black Widow valve and 17 ft of DOT line. Keep the run from the valve to the horn short.
- Mount the filter and drain. The kit includes a remote-mountable filter housing and a drain cock. Put the filter somewhere clean and dry, and drain the tank regularly. Our tank draining guide covers the routine.
- Check your state first. Wire it on a separate switch so your factory horn stays your road horn.
If you’re sizing an air system yourself instead, our compressor buying guide, air tank size guide, and duty cycle explainer explain what the 1NM’s ratings mean in practice.
Sources
- HornBlasters — Nathan AirChime P5 544K Train Horn Kit (HK-P5-544K) — price ($2,799.99, compare-at $2,825.99), reconditioning process, sand-cast aluminum and stainless internals, horn/tank/compressor dimensions and weights, 110/150 PSI switch, 5-6 s blast time, conflicting 90 s vs 2 min recharge figures, 25 A draw, duty cycle, 1.75 CFM flow, fill rates, included items, 5-year/2-year warranty, product photos
- HornBlasters — Nathan AirChime P5 Train Horn (AH-P5) — standalone P5 price ($1,999.99), reversible bells, stainless steel diaphragms, horn-only packaging
- HornBlasters — HornAir 5-Gallon Onboard Air System — HA-544K-HK heavy-duty system price ($659.99) and its included items (wiring kit, fittings, no horn valve or 1/2 in air line) for the build-it-yourself comparison
- HornBlasters — Nathan AirChime K3 544K Train Horn Kit — K3 544K kit price ($2,749.99) and ~7 s honk time
- HornBlasters — Nathan AirChime K5 Train Horn Kit — K5 544K kit price ($4,999.99)
- HornBlasters — Admiral 544 Train Horn Kit — Admiral 544K kit price ($999.99)
- Nathan AirChime — official site — Nathan supplies over 90% of America’s locomotive horns
- Wikipedia — Nathan Manufacturing — P-series 1953 origin and “President’s whistle” name, P5 railroad users, A dominant 7th chord, P5 variants and old vs new cast bells, shared-diaphragm design
Train Horn Hub aggregates publicly available data. We do not test products in-house. All trademarks belong to their respective owners.
The best-value way to get a genuine five-chime Nathan with a complete heavy-duty air system from HornBlasters, ideal for fans of the vintage P-series chord. Buyers on a budget get far more kit per dollar from a HornBlasters-branded 544K kit.
Frequently asked questions
Quick answers to the questions people ask most about this topic.
- How loud is the Nathan P5 544K kit?
- HornBlasters doesn't publish a decibel rating for this kit, so we don't list one. The horn is a genuine, reconditioned Nathan AirChime P5 locomotive horn, the same model Wikipedia documents in passenger and freight railroad service.
- How long can the P5 544K blow on a full tank?
- HornBlasters rates the kit at 5-6 seconds of continuous blast from the 5-gallon tank at 150 PSI. Its fill-rate table puts the 110-150 PSI refill at 2 minutes (±5 s) at 13.8 V, although the marketing copy on the same page says about 90 seconds.
- Is the horn new or used?
- It's reconditioned. HornBlasters says its Nathan horns are sourced from retired locomotives, then sandblasted, refinished in black powder coat, and rebuilt with new diffuser rings, diaphragms, and cushion rings. The horn carries a 5-year warranty, and the rest of the kit has a 2-year defect warranty.
- Is the kit cheaper than buying the horn and air system separately?
- No. The standalone P5 is $1,999.99, and the Heavy-Duty HornAir 5-gallon system without the tire kit is $659.99, about $2,660 combined. The $2,799.99 kit costs roughly $140 more. That air system already includes the wiring and brass fittings, so the extra money mainly buys the Black Widow valve and 17 ft of 1/2 in air line.
- What chord does the P5 play?
- Per Wikipedia, the standard P5 sounds an A dominant 7th chord, the vintage "President's whistle" voice. Variants such as the P5A use a different bell and chord, and the kit page doesn't say which bell set ships, so ask HornBlasters if the exact chord matters to you.
