  PSR J0026-1955 was independently discovered by the Murchison Widefield Array
(MWA) recently. The pulsar exhibits subpulse drifting, where the radio emission
from a pulsar appears to drift in spin phase within the main pulse profile, and
nulling, where the emission ceases briefly. The pulsar showcases a curious case
of drift rate evolution as it exhibits rapid changes between the drift modes
and a gradual evolution in the drift rate within a mode. Here we report new
analysis and results from observations of J0026-1955 made with the upgraded
Giant Meterwave Radio Telescope (uGMRT) at 300-500 MHz. We identify two
distinct subpulse drifting modes: A and B, with mode A sub-categorised into A0,
A1, and A2, depending upon the drift rate evolutionary behaviour. Additionally,
the pulsar exhibits short and long nulls, with an estimated overall nulling
fraction of ~58%, which is lower than the previously reported value. Our
results also provide evidence of subpulse memory across nulls and a consistent
behaviour where mode A2 is often followed by a null. We investigate the drift
rate modulations of J0026-1955 and put forward two different models to explain
the observed drifting behaviour. We suggest that either a change in polar gap
screening or a slow relaxation in the spark configuration could possibly drive
the evolution in drift rates. J0026-1955 belongs to a rare subset of pulsars
which exhibit subpulse drifting, nulling, mode changing, and drift rate
evolution. It is, therefore, an ideal test bed for carousel models and to
uncover the intricacies of pulsar emission physics.

High Energy Astrophysical Phenomena