Insta train is a good way to gain followers fast basically it’s a sort of system which you board and your account follows 40 people and it kicks the last person on that system to make room for you and then someone else boards the system and automatically follows you until you are the last person and kicked of the system and then you can just repeat. I have personally used Insta train and I have found it very good in gaining followers, I gained 500 followers on my main instagram account within 2 days which I found very useful. :)
Insta Train also offers you the chance to become a VIP which you pay $30 for 1 $50 for 3 days $100 for a week and this basically allows your account to stay on the system for that amount of days whilst everyone else continues to follow you.
www.insta-train.net - Insta-train can be found here
www.insta-bus.net - Insta-bus is a service simular to Insta-train which I also recommend :)
Hope this has helped you and remember to follow me @instaresult