The sad reality is that many or most journeys simply are *not* quicker by train.
Commuter journeys in to London or some other cities possibly, but otherwise it's hard to think of any journey where the train has a real advantage.
Even long journeys like London to Glasgow, whilst the point-to-point run may be fast, the reality is that most people won't be starting their journey at Euston. And try doing a journey like Stevenage to Northampton and claim it's quicker by train, even in rush hour! Even Stevenage to Plymouth is quicker by car.
A sad state of affairs, especially as rail travel has generally tended to get slower in recent years.
More people travelling now, whether by road, rail or air, than every before means in many instances that things slow down. Just look at the motorways - they've hardly speeded up over the years.
Rail won't win all of the time, nor should it but there are many routes where rail is preferable to road.
On the specific of Stevenage to Northampton I am
very familiar with this journey by both road and rail. A decent road trip, off-peak, takes around 1h15m.
By rail off-peak you can do it in 1h35, to be fair this doesn't fully meet the minimum connection time but I've never failed to make it by taking the xx06 from Stevenage, changing at Finsbury Park to the Victoria Line and getting the xx49 off Euston.
The reverse journey is fun - take the xx50 from Northampton to Euston, with some very nimble footwork it is possible to make the xx58 from Finsbury Park, arriving into Stevenage at xx16. Journey time 1h26. To be fair it's very, very tight between Euston and Finsbury and you need a kind platform at Euston and to be in the correct position in the train upon arrival at Euston and on the Victoria Line. I make it more often than not though!
