2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/183694Two Galactic isolated strong X-ray pulsars seem to be in the densest environments compared to other types of Galactic pulsar. X-ray pulsar J1846-0258 can be in an early phase of anomalous X-ray pulsars and soft gamma repeaters if its average braking index is ~1.8-2.0. X-ray pulsar J1811-1925 must have a very large average braking index (n~11) if this pulsar was formed by SN 386AD. This X-ray pulsar can be in an early phase of evolution of the radio pulsars located in the region P~50-150 ms and P~10$^{-14}-10^{-16}$ s/s of the P-P diagram. X-ray/radio pulsar J0540-69 seems to be evolving in the direction to the dim isolated thermal neutron star region on the P-P diagram. Possible progenitors of different types of neutron star are also discussed.to appear in the International Journal of Modern Physics DAstrophysicstext