Before we get started on this review it's worth clarifying that there are in fact two Class 20's available now for RailWorks. One is produced by RailSimulator.com (available from Steam) and has been out for a little while now. This is a brand new one released very recently and is available from JustTrains either online or on disc (via the JustTrains store).

The Class 20 or "English Electric Type 1" (Chopper to us enthusiasts!) was a hardworking freight loco in the BR stables. A total of around 220 of them were built between 1957 and 1968. They are principally a mixed freight locomotive, lacking the necessary train heating equipment to run passenger services. That said, there were exceptions to this rule and very occasionally a Class 20 has been known to run a passenger service.

The JustTrains rendition of the Class 20 presents it in a number of liveries:

• British Rail - Blue
• British Rail - Green
• British Rail - Headcode box
• British Rail - Weathered
• DRS (Direct Rail Services)
• DRS - Refurbished
• DRS - Refurbished weathered
• Hunslet Barclay
• Lafarge cement
• Railfreight

I was very impressed with the quality of the texturing in the liveries and was particularly taken by the Railfreight (grey with red stripe) and BR Blue liveries (as these represent the era that I'm generally more drawn to). That said, the other liveries were of a similar standard and I really liked their definition of weathered. As you can see in some of the screenshots, when a train is billed as "weathered" it's absolutely caked up and really looks like a heavily abused loco, very nice, and brings a touch of realism to all those shiney locos we normally see in the simulators.

JustTrains haven't been stingy on cabs either, while testing I particularly appreciated the more clean cab versus the more dirty cab - when you're in a dirty weathered loco, having to look out of a grubby horrible window really adds to the immersion.

Sounds deserve a particularly special mention. While I would normally try to refrain from direct comparisons between two similar products I think it's something that those looking at this pack are going to definitely want to hear about. Well, one area of specific improvement with the JT pack over the RailSimulator.com pack is that the sounds on this loco are absolutely spot on in my view. Where I was very disappointed with the sounds on the Class 20 from RailSimulator.com (at least, as it was released, I don't know if the sounds on it were updated subsequently) I immediately recognised the sounds in this pack. They sound great, and just like the real thing.

So all in all, the loco itself is very good and very nicely presented in a number of variations. This pack doesn't end there though, also included in the pack are two wagon sets.

Rail Head Treatment Train

I thought this was absolutely superb, highly detailed a nice addition that users will have fun running as a different kind of service on their RailWorks routes. Additionally, if you're running it on RailWorks as opposed to Rail Simulator, then you can manually switch on and off the water jets with accompanying visual spray effects. Again, the Weathered version is particularly disgracefully dirty and really looks like it's been severely abused and over used. Excellent stuff.

Nuclear Flask Wagons

The Class 20's often took the nuclear waste trains so it's fitting that they're included in this pack. Included are loaded and unloaded variants although the only diffence between the two is the presence of a sticker, at least you can be accurate to that level in your scenarios :)

There are a few scenarios included in the pack and I found them to be somewhat better than the usual standard included in most add-ons. If you have Newcastle to York Modern (another JustTrains product) then you will find a couple of scenarios for that route as well as for some of the standard default routes. You'll find yourself hauling nuclear waste trains, rail head treatment trains and other freight services around with reasonable AI traffic.

Overall I rate this pack highly, everything that's included is completed to a very high standard. The cab looks lovely (including a suitable driving position when you're running nose-first) and the sounds are absolutely first rate. If you don't have a class 20 pack yet for your system and are considering one then I would have to recommend going for the extra £5 over the RailSimulator.com pack as this one is simply better and contains more. If you already have the RailSimulator.com pack (which, remember, was released more than 6 months ago) then whether this pack is worth your £14.99 is going to be a much more considered decision for you, however with the better sounds and the extra wagons I'd say it's certainly worth that consideration.

A must-have for chopper fan!