[Accessible Japan]

Hello,

Thanks for your question. Those two stations are horrible mazes of confusion!   Here are station maps provided by JR:

• Shinjuku – http://www.jreast.co.jp/e/stations/img/map_e/e866.pdf
• Shibuya – http://www.jreast.co.jp/e/stations/img/map_e/e808.pdf

According to http://pitari-yamanote.juin21.com/yamanote5791.html

At Shinjuku Station:

• For Sotomawari (outside loop): there are escalators at carriages 3, 10, 11 and an elevator at carriage 11
• For Uchimawari (inside loop): there are escalators at carriages 8, 10/11, and an elevator at carriage 11

At Shibuya Station:

• For Sotomawari (outside loop): there is an escalators at carriage 7/8 and elevators at carriage 7 and 9
• For Uchimawari (inside loop): there is an escalators at carriage 5 and an elevator at carriage 3

So, while they are hard to find, and not conveniently located, they do exist.

Hope this helps!