The classic diesel engine seems to have had its day – at least going by the displays at Germany’s IAA Transportation trade fair for commercial vehicles. Electric lorries and vans dominate almost every stand at the Hanover event with manufacturers showcasing their latest battery models and inviting visitors to test drive them. Tesla is also fielding its futuristic electric truck in Germany for the first time at the biannual get-together although the sleek tractor unit does not yet have road approval for Europe. A Tesla official said its engineers were working hard on plans to offer the lorry in…