Well I think you need to articulate the business case. For example: Using Rails will save us '$x' over time and use 'y' less engineers. On the flip side, you

Well I think you need to articulate the business case. For example: Using Rails will save us '$x' over time and use 'y' less engineers. On the flip side, you do have to calculate the ramp up time of learning the technology. To make a convincing argument, try to understand the other person's value system.