The identity will launch next year as part of the livery on the company's Meridian trains, which are undergoing final tests. Existing trains will be rebranded.
Poulter Partners, responsible for the overhaul, based the brand identity on perceived values of European railways, seen by UK passengers as aspirational.
Poulter Partners head of design James Acton said: "We wanted the logo to convey sleekness, speed and reliability. The introduction of the trains is an opportunity to invest in the core values of the brand."
The rebrand replaces the 'stag' identity, created by Saatchi & Saatchi, and used from the mid-90s.
Poulter Partners was hired in 2001, following a pitch that saw the account move out of Cogent, which had held the account since 1997. The interiors of the trains have been designed by Seymour Powell.
The rebrand comes shortly after Midland Mainline received £1.5m in compensation from Network Rail as a result of the disruption at St Pancras station caused by construction of the Channel tunnel rail link. Had it not been for this payment, it would have recorded a half-year loss of £900,000 in September. The company instead increased profits in the same period from £5.1m to £5.7m.
This autumn, Midland Mainline was named as the train operator whose performance had declined the most, with only 68.8% of its services running on time, compared with 83.5% at the same time last year.
Head of marketing and communications Jamie Burles said: "Our passengers clearly felt that the old identity was no longer as relevant or motivating as it used to be. They wanted to see a change with the introduction of the trains."