- +Complete 5-gallon kit at $499.99 — hundreds less than comparable name-brand systems
- +All-metal trumpets and base with a disclosed 307/347/440 Hz low-range chord
- +Tank includes pressure switch, gauge, relief valve, and drain out of the box
- +Built-in 12V solenoid on the horn base simplifies plumbing
- +Unusually complete published spec sheet (Hz, dims, amps, switch pressures)
- −152 dB rating has no disclosed test distance
- −Only a 3-month warranty, with a $20 fee for warranty returns
- −3.5 CFM compressor refills the 5-gallon tank slowly
- −No chrome finish option
- −User reports suggest real-world volume trails the headline number
Methodology
This review aggregates publicly available information from manufacturer specifications, retailer listings, and verified user reviews. We do not perform hands-on testing. Last reviewed: August 10, 2026. Primary sources for this article are Wolo’s official 887-860 product page, Wolo’s printed installation sheets for the Midnight Express horn and the 860 on-board air system, and retailer listings at Summit Racing and Amazon. Every number below comes from those sources, which are listed in full at the end.
Quick verdict
The Midnight Express Pro Plus 887-860 is Wolo’s biggest-tank complete train horn package: the three-trumpet, all-metal Midnight Express horn bolted to a full 5-gallon on-board air system with a 3.5 CFM compressor. At $499.99 direct from Wolo, it undercuts most name-brand 5-gallon kits by a wide margin while still using metal trumpets, brass fittings, and a tank with a built-in pressure switch, gauge, relief valve, and drain. We rate it 3.9/5 — the honk-per-dollar math is genuinely good, but Wolo doesn’t disclose a test distance for its 152 dB claim, and the 3-month warranty is the shortest in the segment.
What it is
The 887-860 is a complete kit built around Wolo’s Midnight Express horn — three metal trumpets on a heavy-duty metal base plate, everything painted semi-gloss black rather than chromed. Per Wolo’s spec sheet, the horn is rated at 152 dB with 90/110 PSI of air (test distance not disclosed) and plays a low-range 307/347/440 Hz chord, which is what gives it that deep, freight-train character instead of the higher bark of small air horns. A heavy-duty 12-volt solenoid valve comes built into the horn base, so there’s no separate valve to plumb.
The “Pro Plus” part is the 860 air system: a 12-volt, 3.5 CFM oil-less compressor feeding a 5-gallon metal tank through a stainless steel braided hose. The tank arrives with the pressure switch, gauge, safety relief valve, petcock water drain, and brass fittings already provisioned — a notably complete setup at this price. The target buyer is a pickup, semi, or RV owner who wants a real train-horn chord and enough stored air for repeated long blasts without piecing together a custom system. For background on why tank volume matters, see our air tank size guide.
Specifications
| Spec | Value |
|---|---|
| Sound output | 152 dB at 90/110 PSI (test distance not disclosed) |
| Chord | 307/347/440 Hz — low range, 3-note |
| Trumpets | 3, all metal, semi-gloss black; metal base plate |
| Horn size | 16.5 in L x 14.75 in W x 11 in H |
| Solenoid | Built-in heavy-duty 12 V electric valve, 250 mA draw |
| Compressor | 12 V permanent-magnet, gearless, oil-less, 3.5 CFM, 22 A peak, washable air filter, thermal protection |
| Compressor size | 11.5 in L x 3.5 in W x 6.5 in H |
| Tank | 5-gallon metal, built-in pressure switch (on 80 / off 110 PSI), gauge, safety relief valve, petcock drain |
| Tank size | 20.5 in L x 8.5 in W x 10.5 in H (17.5 in H with compressor mounted on tank) |
| Air lines | 10 ft flexible high-pressure hose (1/4 in O.D.) + 20 ft coiled filler hose; brass fittings |
| Shipping weight | 39 lbs |
| Power | 12-volt vehicle electrical system |
| Price | $499.99 (Wolo direct) |
| Warranty | 3 months, original purchaser |
One aggregation note for accuracy: Wolo’s current product page lists the pressure switch at 80 PSI on / 110 PSI off, while the printed 860 air-system install sheet describes the compressor shutting off around 120 PSI. We defer to the current product page, but expect the shutoff to land in that 110–120 PSI window.
What’s in the box
- Midnight Express three-trumpet metal horn with mounting base and built-in 12 V solenoid
- 860 on-board air system: 3.5 CFM 12 V compressor + 5-gallon metal tank
- Pressure switch (built into tank), pressure gauge, safety relief valve, petcock water drain
- Extended-length stainless steel high-pressure hose (compressor to tank)
- 10 ft of flexible 1/4 in O.D. high-pressure hose + 20 ft coiled filler hose
- Brass air fittings and stainless steel mounting hardware
Pros
- Complete 5-gallon system for $499.99 — hundreds less than comparable name-brand 5-gallon kits
- All-metal trumpets and base with a true low-range 307/347/440 Hz three-note chord, fully disclosed by the manufacturer
- Tank ships with pressure switch, gauge, relief valve, and drain built in — less plumbing to source and fewer leak points
- Built-in solenoid on the horn base simplifies installation
- Oil-less, gearless permanent-magnet compressor with thermal protection and a washable air filter
- Spec sheet is unusually complete: Hz, dimensions, amp draw, and switch pressures are all published
Cons
- The 152 dB rating has no disclosed test distance, so it can’t be compared directly to honestly rated competitors
- 3-month warranty is far shorter than the 1-year-plus coverage typical of HornBlasters or Kleinn, and warranty returns require a $20 shipping fee
- 3.5 CFM compressor will take noticeably longer to fill 5 gallons to 110 PSI than the higher-output compressors in premium kits
- Semi-gloss black finish only — no chrome option for this model
- Some user reports on retail listings say real-world volume is lower than the headline number suggests, usually tied to low tank pressure
Alternatives
- HornBlasters Conductor’s Special 228H — the benchmark 2-gallon kit with honestly rated Shocker horns and a lifetime horn warranty, at a higher price. See our full review.
- Wolo 837 Cannon Ball Express — Wolo’s roof-mount single-trumpet alternative if you want the look of a cab horn rather than a hidden three-trumpet cluster. See our 837 Cannon Ball Express review.
- Wolo 847 Siberian Express — the 887’s stablemate with a different trumpet arrangement and the same Wolo air-system options. See our 847 Siberian Express review.
More Wolo coverage lives on our Wolo reviews hub.
Install / compatibility notes
This is a 12-volt system, so it fits any standard car, pickup, SUV, RV, or boat electrical system (Wolo sells the Model 888 for 24-volt trucks). Plan a day for a clean install: you’re mounting the horn, the tank, and the compressor, then running both air and wiring.
- Mount the horn to a solid metal surface — Wolo’s instructions specifically warn against fender-well mounting.
- Mount the 5-gallon tank (frame rail or bed) and the compressor; the extended stainless hose lets the compressor sit on a surface away from the tank, or you can mount it directly on top for a 17.5 in tall combined unit.
- Wire the compressor’s pressure-switch circuit through a 25-amp fuse and the horn solenoid circuit through a 6-amp fuse (fuses not included), per Wolo’s install sheets. Our relay wiring guide covers the safe way to trigger the solenoid from a button or your stock horn.
- Connect the 1/4 in air line from tank to solenoid, fill to cutoff pressure, and soap-test every fitting.
The compressor carries thermal protection; Wolo’s sheet says that if it trips before the tank fills, you should let it cool roughly 40 minutes. That’s normal behavior for a compact single compressor filling five gallons — our duty cycle guide explains what to expect. Remember that at 152 dB advertised, this is strictly an off-road / private-property toy in most states; check your state’s page in our legal section before wiring it to your stock horn button.
Sources
- Wolo — Model 887-860 Midnight Express Pro Plus product page — all primary specs: 152 dB at 90/110 PSI, 307/347/440 Hz, horn/compressor/tank dimensions, 3.5 CFM, 22 A peak, 80/110 PSI pressure switch, included items, 39 lb shipping weight, $499.99 price
- Wolo — Midnight Express horn installation instructions (PDF) — mounting cautions, 6-amp solenoid fuse, 3-month warranty terms and $20 return-shipping requirement
- Wolo — 860 on-board air system installation instructions (PDF) — 25-amp compressor fuse, pressure-switch behavior, ~40-minute thermal cooldown note, warranty text
- Summit Racing — Wolo 887 Midnight Express listing — retailer cross-check for the bare 887 horn specs and availability
- Amazon — Wolo 887 Black Midnight Express listing — retailer availability and source of aggregated user feedback on real-world loudness
- Wolo — Model 887-858 Midnight Express Pro product page — confirms the 887-858 is the smaller package with a 2.55 CFM compressor and 2.5-gallon tank
- Wolo — Model 888 Midnight Express 24-Volt product page — existence of the 24-volt Model 888 variant
- HornBlasters — Conductor’s Special 228H product page — 2-gallon tank, lifetime horn warranty, and current price for the alternative pick
Train Horn Hub aggregates publicly available data. We do not test products in-house. All trademarks belong to their respective owners.
The best pick for a buyer who wants a genuine low-range three-trumpet chord and a full 5-gallon air system on a $500 budget and can live with a short warranty. Buyers who want honestly distance-rated decibels or long-term coverage should step up to a HornBlasters kit.
Frequently asked questions
Quick answers to the questions people ask most about this topic.
- How loud is the Wolo Midnight Express Pro Plus 887-860 really?
- Wolo rates the horn at 152 dB when fed 90–110 PSI, but does not disclose the test distance, so the number can't be compared directly to distance-rated competitors. Some user reports on retail listings describe real-world output as less dramatic than the rating implies, especially at lower tank pressures.
- What's the difference between the 887, 887-858, and 887-860?
- The bare Model 887 is the horn only and requires an on-board air source you supply. The 887-858 bundles the horn with Wolo's smaller Pro air system, while the 887-860 reviewed here is the Pro Plus package with the 3.5 CFM compressor and full 5-gallon tank.
- How long does the compressor take to fill the 5-gallon tank?
- Wolo doesn't publish a fill time. At 3.5 CFM the first fill from empty to the 110 PSI cutoff takes several minutes, and the compressor's thermal protection may pause it — Wolo's install sheet says to allow roughly 40 minutes of cooling if that happens.
- Does the kit include everything needed to install it?
- Almost. The kit includes the horn with built-in solenoid, compressor, 5-gallon tank with pressure switch, gauge, relief valve and drain, hoses, brass fittings, and stainless mounting hardware. You'll still need wire, a 25-amp fuse for the compressor circuit, a 6-amp fuse for the solenoid, and a horn button or relay setup.
- Is the Wolo 887-860 street legal?
- Train horns rated this loud are generally not legal to use on public roads in most US states, though laws vary on installation versus use. Treat it as an off-road, event, or private-property horn and check your state's rules before wiring it as your primary horn.
