- +Genuine low-range three-chime chord with disclosed 307/347/440 Hz frequencies
- +Unusually complete published spec sheet — PSI, dimensions, solenoid draw, materials
- +Reinforced-ABS build keeps weight down and resists road vibration
- +Complete hookup kit: 12V solenoid, 10 ft hose, brass fittings, stainless hardware
- +$149.99 horn-only price undercuts most metal triple-trumpet competitors
- +Matched 847-858 PRO combo adds a 2.5-gallon air system in one purchase
- −152 dB rating has no disclosed test distance
- −Needs a 90-110 PSI onboard air system — add $250-290 for Wolo's recommended compressors
- −ABS trumpets lack the durability reputation of spun-metal horns
- −Out of stock at Wolo and temporarily unavailable at RealTruck at time of writing
- −Only a 1-year warranty
- −Large 16.5" x 14.75" footprint demands serious mounting space
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 on July 16, 2026, this article draws on Wolo’s official product pages for the Model 847 and the 847-858 Siberian Express PRO combo, retailer listings from RealTruck, Zoro, Summit Racing, and Amazon, and publicly posted video demonstrations. Every number below traces back to a URL in the Sources section at the end.
Quick verdict
The Wolo 847 Siberian Express earns a 3.8/5 from us. Wolo publishes an unusually complete spec sheet — exact chord frequencies, operating pressure, solenoid current draw, full dimensions — which is more transparency than many competitors manage, and the $149.99 horn-only price undercuts most metal triple-trumpet rivals. The reinforced-ABS construction is the honest trade-off: lighter and cheaper than spun brass or chrome-plated steel, but without the durability reputation of metal horns. And like every true train horn, the 847 does nothing on its own — budget for an onboard air system, which Wolo’s own recommendations price at $249.99 and up.
What it is
The Siberian Express Model 847 is a 12-volt, three-trumpet train horn built for trucks that already have — or plan to add — an onboard air system. The three trumpets are molded from reinforced ABS, sit on an enamel-painted base, and wear a semi-gloss black finish. Wolo says the reinforced plastic was a deliberate choice: it cuts overall weight, which makes installation easier and reduces vibration on rough roads compared with heavy metal trumpets.
The acoustic pitch is what separates a train horn from a loud air horn. Per Wolo’s spec sheet, the three trumpets are tuned to 307, 347, and 440 Hz — a low-range chord that Wolo says gives a truck “the powerful sound of a train air horn”. Output is rated at 152 dB (test distance not disclosed) with the horn fed 90–110 PSI of air. In publicly posted video demos of the Model 847, the horn delivers the layered, dissonant multi-chime blast people expect from a locomotive rather than a single flat tone — though video audio compression means demos are a rough guide at best. We explain why trumpet chords matter in our chord and trumpet tuning guide.
Wolo sells the Siberian Express two ways: the horn-only Model 847 at $149.99, and the 847-858 Siberian Express PRO combo at $379.99 direct, which bundles the horn with a 2.5-gallon onboard air system. More on that split below. For the brand’s full lineup, see our Wolo reviews hub.
Specifications
| Spec | Value |
|---|---|
| Model | Wolo 847 Siberian Express |
| Sound output | 152 dB (test distance not disclosed) |
| Chord | 307 / 347 / 440 Hz, low range |
| Trumpets | 3, reinforced ABS, semi-gloss black finish |
| Operating pressure | 90–110 PSI |
| Voltage | 12V |
| Solenoid valve | Heavy-duty 12V electric, 300 mA draw |
| Dimensions | 16.5” L × 14.75” W × 11” H |
| Base | Painted enamel |
| Air source | Onboard air system required (not included with the 847) |
| Price | $149.99 (horn only); $379.99 (847-858 PRO combo, direct) |
| Warranty | 1 year against defects in materials and workmanship |
A note on that headline number: Wolo does not state the distance at which 152 dB was measured, and per the physics of sound, the same horn reads dramatically different at 3 feet versus 100 feet. Treat 152 dB as a manufacturer claim, not a guaranteed real-world reading — our advertised vs. real-world decibels guide covers why almost every brand’s number needs that asterisk.
What’s in the box
The standalone Model 847 ships as a horn kit, not a complete system:
- Three-trumpet Siberian Express horn assembly
- Heavy-duty 12-volt electric solenoid valve
- 10 feet of 1/4” nylon high-pressure hose
- Brass air fittings
- Stainless steel mounting hardware
What it does not include is air. If you want a single-box solution, the 847-858 Siberian Express PRO pairs the same horn with Wolo’s 2.5-gallon air system: a 12-volt oil-less compressor rated at 21 amps peak, 2.55 CFM, and a 33% duty cycle at 100 PSI, plus a tank with an 80 PSI on / 110 PSI off pressure switch, pressure gauge, relief valve, water drain, and a 20-foot coiled filler hose. Wolo lists the PRO at $379.99; at press time Zoro carried it for $336.99. If you’re weighing the combo against building your own air setup, our compressor buying guide and air tank size guide break down the math.
Pros
- Genuine low-range three-chime chord (307/347/440 Hz) — disclosed frequencies, not marketing vagueness
- Unusually complete published spec sheet: PSI, dimensions, solenoid draw, materials all documented
- Reinforced-ABS build keeps weight down, easing installation and resisting road vibration
- Complete hookup kit included — solenoid, 10 ft hose, brass fittings, stainless hardware
- $149.99 horn-only price undercuts most metal triple-trumpet competitors
- Matched PRO combo (847-858) available for buyers who want horn and air in one purchase
Cons
- 152 dB rating carries no disclosed test distance, so real-world loudness is hard to pin down
- Requires a 90–110 PSI onboard air system — true cost is the horn plus $250–290 for Wolo’s recommended compressors
- ABS trumpets lack the durability reputation and resale appeal of spun-metal horns
- Listed as out of stock on Wolo’s own site and temporarily unavailable at RealTruck at the time of writing
- Warranty runs only one year, shorter than some competitors’ coverage
- Large 16.5” × 14.75” footprint demands real mounting space under a truck
Alternatives
- Wolo Quadraphonic Express PRO 877-858 — the four-trumpet sibling sold bundled with the same 2.5-gallon Tornado air system; the natural step up inside Wolo’s own line.
- Kleinn 230 — a triple-trumpet competitor from the other big name in vehicle train horns, worth cross-shopping on build and price.
- Vixen Horns VXH3318B — a budget-priced three-trumpet option if the Siberian Express stretches the budget once you add air.
Install / compatibility notes
The 847 is strictly an onboard-air horn — there is no tankless or electric mode. Wolo recommends three of its own air systems: the Model 840 Turbo ($249.99), Model 858 Tornado ($264.99), or Model 860 Air Rage ($289.99). Any third-party system that sustains 90–110 PSI will also drive it; our PSI guide explains what happens to volume and tone when pressure sags below spec.
Electrically, the horn itself is easy on a 12-volt system — the solenoid valve draws just 300 milliamps, so the horn button circuit is trivial. The compressor is the hungry component (21 amps peak on the PRO’s pump), and that’s the circuit that needs proper wire gauge, fusing, and a relay; see our relay wiring guide and amp draw and fuse sizing guide.
Physically, plan for the footprint: at 16.5 inches long and nearly 15 inches wide, the 847 wants frame-rail or under-bed real estate, mounted trumpets-forward and slightly down so water drains out. Our mounting location guide walks through the best spots on a pickup. User feedback on retailer listings is thin but positive on sound — RealTruck shows a 4.3/5 average across four reviews of the PRO combo, and retailer reviewers describe the output as loud and crisp, with price after adding air being the recurring complaint (user reports, not our measurements). Before you install anything this loud, check your state’s rules in our legality guides.
Sources
- Wolo — Model 847 Siberian Express product page — price ($149.99), 152 dB rating, 307/347/440 Hz chord, 90/110 PSI, dimensions, ABS construction, solenoid spec (12V/300 mA), included items, recommended air systems (840/858/860), stock status
- Wolo — Model 847-858 Siberian Express PRO product page — PRO combo price ($379.99), 2.5-gallon tank, compressor specs (21A peak, 2.55 CFM, 33% duty at 100 PSI), 80/110 pressure switch, included hoses
- RealTruck — Wolo Siberian Express Pro 847-858 listing — 152 dB cross-check, 1-year warranty terms, 4.3/5 user rating (4 reviews), availability status
- Zoro — Wolo Siberian Express PRO 847-858 listing — PRO combo street price ($336.99)
- Summit Racing — Wolo 847 listing — retail availability of the standalone 847
- Amazon — Wolo 847 Siberian Express listing — retail availability cross-check
- YouTube — Wolo Model 847 Siberian Express Triple Trumpet Air Horn — sound demonstration
- YouTube — Wolo Siberian Express 847 Train Horn — independent sound demonstration
Train Horn Hub aggregates publicly available data. We do not test products in-house. All trademarks belong to their respective owners.
The Siberian Express is the right pick for truck owners who want an honest, fully spec'd three-chime train horn without metal-horn weight or price — just budget for the 90-110 PSI onboard air system it requires, or buy the 847-858 PRO combo and be done in one box.
Frequently asked questions
Quick answers to the questions people ask most about this topic.
- How loud is the Wolo 847 Siberian Express really?
- Wolo rates the 847 at 152 dB with a 307/347/440 Hz low-range chord, but does not disclose the test distance for that number. Treat it as a manufacturer claim — real-world readings at typical distances will be lower, as with virtually every train horn on the market.
- Does the Wolo 847 come with an air compressor and tank?
- No. The standalone Model 847 includes the horn, a 12V solenoid valve, 10 feet of 1/4" hose, fittings, and mounting hardware, but no air source. You need an onboard air system delivering 90-110 PSI, or you can buy the 847-858 Siberian Express PRO combo, which bundles a 2.5-gallon compressor-and-tank system.
- What PSI does the Siberian Express need?
- Wolo specifies 90-110 PSI operating pressure. Its recommended air systems — the 840 Turbo, 858 Tornado, and 860 Air Rage — are all built around that range, and the PRO combo's pressure switch cycles between 80 and 110 PSI.
- What is the difference between the 847 and the 847-858 PRO?
- The 847 is the horn kit alone at $149.99. The 847-858 Siberian Express PRO ($379.99 direct, seen lower at retailers) adds Wolo's 2.5-gallon onboard air system: a 12V oil-less compressor rated at 2.55 CFM with a 33% duty cycle, plus a tank with pressure switch, gauge, relief valve, and filler hose.
- Is the Wolo 847 street legal?
- It depends on your state. Many states restrict horn loudness or reserve train-horn-style devices for off-road and emergency use, so check your local vehicle code before installing and using one on public roads.
