Great Northern Siemens Desiro City Class 717 acceleration 0-70mph

Great Northern's new Class 717 entered service on Monday 25th March 2019 - after months of delays. Are they any faster than the 40-year old class 313 trains that they replace? We took a trip to find out. The unit we travelled aboard was 717005 an a stopping service to Welwyn Garden City. Departure northbound faces an uphill gradient of 1 in 200 as far as Potters Bar. Can the 717's beat the 313's and enter the tunnel mouth at more than the older trains 60mph? Lets find out...