Oops!

Half of his train was correct; he couldn't raise the pantograph on the rear 4 and had to "phone a friend" before figuring out there wasn't one!

Not realising that the unit you're driving doesn't have a pantograph would be quite an impressive feat (presumably there wouldn't be a "raise pantograph" button?)

I believe from my contact that a unit sustained panto damage, the remains being removed at a overnight stabling depot (south of Thames) which didn't hold the required spares, but was OK for service. Unit to be worked back to home depot for repairs.... I think you can see where this is going.

There is a story from the Sou'Western back in the 1980s, of a driver who relieved an up road (4-TC leading) at Basingstoke. (I should explain that the 4-TCs were unpowered but otherwise not easily distinguishable from main-line Southern EMUs of that generation; they were designed to be pushed from Waterloo to Bournemouth by a 4-REP, a high-power EMU built specially for that duty, then at Bournemouth they would hook off the REP and couple to an adapted cl33 to work push-pull to Weymouth, loco leading on the down run and pushing on the return so they could run straight on to the waiting REP and depart after a hardly-longer-than-usual station stop.)

As he drove up to London he found acceleration was none too brilliant; certainly not what you'd expect from a 4-REP, even with a couple of 4-TCs to shove. But top speed was still OK and there are plenty of reasons for lack of power so he thought nothing of it. Duly arrived at Waterloo, he screwed the unit down and, as booked, went to the mess room for PNB.

As he settled to his sandwich, an announcement came over the tannoy asking the driver who'd brought a loco in to go and move it. He took no notice then, nor when it was repeated a few minutes later. Eventually, the Traincrew Supervisor accosted him in person, asking him what train he'd brought in then requesting him to move the offending loco. He denied ever having moved the loco concerned: "I can't, I'm a 'Juice Jockey'" (i.e. not trained on diesel traction). It was only when taken down and walked along the platform that he realised the train he'd relieved was an up Salisbury and he'd been driving an 8-TC with a 33 shoving from the rear! (It was said he never again relieved a train without first checking the back end as well as the front.)