The construction of the Standard Gauge Railway from Nairobi to Naivasha will now cost Sh2.02 billion more.
This comes after environmentalists raised concerns over the route used by the railway stating that it might have a negative impact on the environment more specifically the Nairobi National Park.
Confirming the news on Wednesday, Kenya Railways MD Atnas Maina said that the 120km route will cost sh150 billion.
"The modification of the route along the Savannah of the Nairobi National Park will be more costly since it will require several enhancements to make it 400 meters shorter than the initially preferred route that would have cut through the park for 6.4 kilometers," said Maina.
The new phase is set to begin this month.
Earlier on conservatives had raised concerns over the impact of the SGR on wild animals if it passed through the park.
This forced the government re-design the initial plan.
In the new plan, the railway will be suspended on a bridge to avoid harming the animals.
"Average height of the bridge above the ground will be 18 meters starting from eight meters at the entrance into the northern side of the park and 41 meters at the southern end of the park ," added Maina.