President Kenyatta on Wednesday inaugurated the Nairobi-Suswa SGR line (Phase 2A) accompanied by First Lady Margaret Kenyatta.
The inagural trip started 12.13pm.
The SGR final stop is Suswa, 100 km away from Nairobi station.
Phase 2A to Naivasha passes through the five counties of Nairobi, Kajiado, Kiambu, Nakuru and Narok.
The completion date of the Nairobi-Naivasha section of the Standard Gauge Railway had previously been rescheduled.
The contractor had said it would be unable to meet the June deadline for the multibillion-shilling second phase of the rail network and instead gave a new August date.
Chinese Communications Construction Company (CCCC) blamed the delay on the compensation row in the Ngong area.
"The problem is not ours, it is a government issue because the responsibility on land compensation and relocation should be the employer’s, " the contractor said.
