I'd like to go on one at least once in my lifetime, but it doesn't look like I'll be able to go anytime soon, so I'd appreciate any information you could give me. I have a question for people who have actually ridden a Class 802. Is there a difference in acceleration and deceleration power between diesel mode and electric mode? Can I experience it as a crew member or passenger?
Yes they have different acceleration performance depending on their power mode. Under AC the power to weight ratio is around 30% higher. There are differences between the 5 & 9 car units, with the 9 car having higher performance due to the higher rate of power to weight. Under diesel power the units are also restricted to a max speed of 110mph vs 125mph under AC. For an even bigger difference, you can try to find a bi mode journey made by a class 800, as their diesel engines are less powerful than the 802, so the power difference between the 2 modes are even wider.
Going from Swindon to Bath or Bristol TM you certainly notice the difference after the power changeover at Chippenham. Slower acceleration on diesel leaving Chippenham towards Bath, but in the other direction you definiteLy feel a kick once the AC kicks in. That said, they are still pretty beefy on diesel power. Been up the Stroud Valley a few times recently. Leaving Stroud it’s pretty much solid 1 in 60 up to Sapperton Tunnel albeit with a 50 MPH speed restriction most of the way. On each occasion the driver was constantly having to throttle back to control the speed.
Thank you both so much for your kind replies. So there is a difference in performance depending on the mode. ・For the class 800, 801 is mainly electric, with the diesel engine being secondary, and is the top speed around 25 mph, is that correct? The 802 has a beefed up diesel engine and a larger fuel tank, so I thought it could be driven at 125mph in diesel mode, but is it doing 125mph electric and 110mph diesel? ・Will the red and yellow circle and square buttons on TPWS be used within TSW?
Class 800, 802, 805 & 810 are all Bi-Mode. All AT-300series units have max diesel speeds of 110mph. The 810 though will be the most powerful diesel unit of all of them. The 800’s I believe had an original design of 100mph max under diesel mode, I’m not sure if they entered service with that limit, or if they only changed to 110mph after GWR increased the engine power on them. Yes the 802 does indeed have larger fuel tanks with more powerful engines, which makes them the primary traction on bi-mode routes, though of course you still get 800’s making it onto them now & then. Class 801, 803 & 807 are all Electric only, the 801 is the only one of these which has the backup diesel engine. I’m not sure what LNER allow drivers to reach on the diesel but I’m pretty sure it’s rated for 40mph. TPWS should work on them, but I haven’t ran into a circumstance where I’ve triggered the penalty for it, which would be the only time you need to interact with the panel. All of the AT-300’s are capable of doing 140mph should we ever get line upgrades to do so, there was an overspeed incident where a TPE 802 hit 145mph in service, due to driver error with the speed set. I think the record for the various classes sits at 148mph though. Of course if you’re interested in higher speed operations of the AT-300, the class 395 is the original AT-300 which has an in service max speed of 140mph. It’s also unique in being the only one that has third rail capability.
