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Guide 16 April 2026

Class 66 vs Class 88: Which UK Locomotive Should You Spot?

Class 66 vs Class 88: Which UK Locomotive Should You Spot?

If you're a trainspotter on UK railways, you'll quickly notice two locomotives dominating the freight lines: the Class 66 and the Class 88. These aren't your typical heritage steam engines—they're the modern workhorses that keep British freight moving. But what's the difference between them? Which one should you prioritize spotting? And where are you most likely to see them?

The answer isn't simple. One is ubiquitous. The other is rarer than a steam loco on the mainline. One runs on diesel alone. The other harnesses electric power and diesel. For the serious trainspotter—whether you're chasing frequency or rarity—understanding these two classes is essential.

Class 66: The Ubiquitous Diesel

The Workhorse That Never Quits

The British Rail Class 66 has been the backbone of UK freight since the mid-1990s. Over 400 locomotives have been built and delivered globally, with more than 250 in UK service across multiple operators. It's not glamorous, but it works.

The Class 66 is a six-axle diesel-electric locomotive developed from the earlier Class 59, built by Electro-Motive Diesel (EMD) in the USA. When you see a freight train rumbling past a level crossing, odds are it's being hauled by a 66. They're that common.

Key Specs:

  • Type: Six-axle (Co-Co) diesel-electric
  • Power: ~3,100 horsepower
  • Traction Motors: EMD D43
  • Engine: EMD 710 prime mover, 2-stroke
  • Max Speed: 75 mph
  • Weight: ~130 tonnes
  • Introduced: 1995
  • Total Built: 455+ globally (250+ in UK)

The "Red Death" and Its Legacy

When Class 66s arrived in the UK in 1995, they displaced hundreds of older locomotives—so many that enthusiasts nicknamed them "The Red Death." The EWS (English Welsh & Scottish) locos, painted in distinctive red and yellow livery, featured an unusual upturned roof that earned them the ironic nickname "Sheds." Freightliner's green and yellow locomotives became known as "Freds" (a blend of "Freightliner" and "Shed").

But the Class 66's real weakness emerged over time. Its 2-stroke EMD engine is notoriously inefficient and doesn't meet modern EU emissions standards. Operating costs are high, wheel wear is accelerated, and driver comfort is—let's be diplomatic—not a priority. By the 2010s, freight operators began looking for alternatives.

The Livery Spotter's Paradise

Here's where Class 66s get genuinely exciting: they come in more different liveries than almost any other UK freight locomotive. This is a livery spotter's treasure trove.

Major Liveries You'll See:

  • EWS/DB Schenker (DB Red): The classic red livery of EWS (now DB Cargo UK). Originally featured bright red and yellow with Beasties logos. These are everywhere.
  • DB Cargo UK: After rebranding from EWS in 2009, many received fresh bright red livery.
  • Freightliner (Dark Green): The distinctive dark green and yellow used by Freightliner. After Genesee & Wyoming's 2026 takeover, new orange and yellow schemes are rolling out.
  • GB Railfreight (Blue): Bright blue and yellow livery. GBRf has been particularly adventurous with special schemes.
  • Colas Rail (Maroon/Black): Smaller operator with their own distinctive scheme.
  • Biffa (Waste Management Partner): 66783 "The Flying Dustman" in Biffa corporate colours—a charming tribute.
  • Brighton Pride (Rainbow Livery): 66773 sports a full rainbow livery in support of LGBT+ rail workers—genuinely stunning.
  • BR Large Logo Blue (Historic Scheme): 66789 returned to retro BR Large Logo Blue, named appropriately "British Rail 1948-1997."
  • Single Operator Schemes: Special liveries for Cemex, Maritime International, Europorte, and others.
  • European Export: Some 66s have been exported to continental Europe and operate in Germany, France, and Poland under different numbering.

If you're collecting "different liveries," a Class 66 list could keep you spotting for months. In fact, class 66s offer the most diverse livery variation of any UK diesel locomotive—more than older classes, more than newer competitors.

Where to Spot Class 66s

Class 66s are everywhere. You'll see them on:

  • East Coast Main Line (ECML): Frequent Tesco trains, intermodal services, coal/biomass trains
  • West Coast Main Line (WCML): Heavy freight between England and Scotland
  • Midland Main Line: Freight corridors through the East Midlands
  • South Coast: Cross-London distribution and container trains
  • Scotland: Inverurie and Mossend yards; North Blyth coal trains
  • Level Crossings: If you're at any level crossing on a mainline, you'll see a 66 within an hour

The most common trains they work are:

  • Intermodal containers (especially Tesco trains 4S44 Daventry-Mossend, 6S42 Southampton-Mossend)
  • Automotive trains (car distribution)
  • Coal/biomass (reduced post-2023 but still running)
  • Domestic freight (parcels, containers, autoparts)

Class 88: The Rare Dual-Mode Innovation

The Electric Future Arrives

The British Rail Class 88 is the opposite of the Class 66 in nearly every way. Only 10 have been built—all for Direct Rail Services (DRS). They're rare, advanced, and represent the future of UK freight.

The Class 88 is a dual-mode (electro-diesel) locomotive—the first of its kind in the UK to use 25kV AC overhead electrification. Vossloh España (now Stadler Rail) developed them as an evolution of the Class 68, specifically to address the Class 66's operational and emissions weaknesses.

Key Specs:

  • Type: Four-axle (Bo-Bo) dual-mode electro-diesel
  • Electric Power: 5,400 horsepower (4,000 kW)
  • Diesel Power: 940 horsepower (708 kW Caterpillar C27)
  • Diesel Range: Up to 500 miles on diesel alone
  • Max Speed: 100 mph
  • Weight: ~92 tonnes (lighter than 66s)
  • Introduced: 2017
  • Total Built: 10 (all for DRS)
  • Manufacturer: Stadler Rail, Valencia, Spain

The Intelligent Design

What makes the Class 88 special isn't just that it runs on electricity. It's smart:

  1. Regenerative Braking: When descending or braking, energy feeds back into overhead lines—a first for UK freight.
  2. Dynamic Mode Switching: The locomotive seamlessly switches between electric and diesel modes without stopping.
  3. Lightweight Design: At 92 tonnes, it's 38 tonnes lighter than a Class 66. This reduces track wear and wheel wear significantly.
  4. "Last Mile" Capability: The 708kW diesel engine, rated at only 940 hp, is designed for depot shunting and unelectrified branch lines—not mainline hauling. Contrast this to the Class 66's 2-stroke engine, which wastes fuel on the mainline where it's not needed.
  5. Efficient Power Plant: The Euro IIIB-compliant Caterpillar diesel meets EU emissions standards. The Class 66's old 2-stroke doesn't.

The genius is operational: When running under overhead lines, the 88 uses pure electric power and eliminates diesel emissions, noise, and fuel costs on the electrified network. Only on non-electrified sidings and depots does it fire up the diesel.

Where You'll See Class 88s

Class 88s work the highest-value, electrified routes where efficiency matters most:

  • Daventry-Mossend Intermodal (4S44/4S42): Primarily Tesco trains. A single 88 replaced two Class 68s on this route, running the same timetable in electric mode.
  • Nuclear Flask Trains: DRS operates sensitive nuclear waste trains that benefit from the 88's advanced control systems.
  • ECML Container Traffic: Intermodal services on electrified sections.
  • Caledonian Sleeper Mixed Freight: Occasional passenger-capable freight trains.

Class 88s are concentrated on Scotland-England routes where the ECML and Caledonian Main Line offer sustained electrification.

Head-to-Head Comparison

Feature Class 66 Class 88
Frequency COMMON (400+ built) RARE (10 built)
Liveries Many (5+ standard schemes) Limited (DRS only)
Power Source Diesel only (inefficient 2-stroke) Electric + diesel (smart switching)
Mainline Power 3,100 hp diesel 5,400 hp electric, 940 hp diesel
Max Speed 75 mph 100 mph
Weight 130 tonnes 92 tonnes
Emissions High (fails EU standards) Low (EU compliant)
Operating Cost High Low (electric power cheaper than diesel)
Regenerative Braking No Yes
Spotting Difficulty Easy (see one daily) Hard (rare sightings)
Collector Appeal High (diverse liveries) High (future tech, rarity)

Which Should You Spot First?

If you're a beginner trainspotter: Start with Class 66s. You'll see them frequently at any UK level crossing. Build your livery collection. Spot the rare special schemes (Brighton Pride, Biffa, etc.).

If you're an experienced spotter: Chase the Class 88s. Rarity equals bragging rights. An 88 is a genuine prize. Plan trips to the Daventry-Mossend intermodal route or Scotland when you know an 88 is scheduled. Check DRS traction notices.

If you want both: That's the real victory. A diverse Class 66 collection (especially special liveries) combined with an 88 sighting makes for a comprehensive UK freight portfolio.

The Future of Freight

The Class 88's arrival signals an important shift: the future of UK freight is electric. DRS's success with these locomotives has already prompted Rail Operations Group (ROG) to order the even more advanced Class 93 (an 88 derivative with battery storage). Meanwhile, the Class 66 is aging. No new ones are being built; EU emissions regulations stopped production in 2016.

Within 10-20 years, as freight operators electrify and modernize, the Class 66 will slowly disappear. The dual-mode/electric classes (88, 93, and beyond) will become the norm.

That makes spotting a Class 66 today more valuable than ever—you're documenting a transitional era in UK freight history.

Spotting Tips & Level Crossing Strategy

For Class 66

  • Best Times: Early morning and late afternoon (peak intermodal windows)
  • Best Routes: Daventry-Mossend corridor (constant Tesco trains), WCML north of Birmingham, ECML in East Anglia
  • Equipment: Bring a camera with good zoom—freight trains move fast. Stock photos of 66 liveries beforehand to ID special schemes quickly.
  • Track Notices: Check RailUK Forums and Trainspots for special workings (heritage trains, chartered freights with unusual locos).

For Class 88

  • Best Times: Check DRS working timetables (published weekly). 4S44 runs Tuesday-Friday, early morning.
  • Best Location: Lichfield Trent Valley on the WCML (iconic 88 filming spot). Mossend Yard approach in Scotland.
  • Persistence: 88s are rare enough that you may need multiple attempts. Plan a dedicated "88 chase" trip.
  • Documentation: When you spot one, it's worth recording the number, time, and weather—rare locos deserve proper logging.

The Bigger Picture

The Class 66 vs. Class 88 comparison isn't just about two different locomotives. It's a window into how UK railways are modernizing. The 66 represents the 1990s-2000s approach: cheap, mass-produced, reliable-enough diesel traction. The 88 represents the 2010s-2020s shift: efficient, electrified, sustainable, smart.

As a trainspotter, you're witnessing a transition. The Class 66's era is ending. The Class 88's era is just beginning. Spotting both gives you a complete picture of modern UK freight history.

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