of course it is....but it needs funding and one key issue we have right now is that we need to borrow to invest and because of the tories economic failures it is now more expensive to borrow because we've lost our AAA rating. Debt is completely acceptable under certain parameters.
The tories always like to use the credit card example when they talk about labour taking on debt (despite the tories taking on far more for no gain), but that isn't a good example of incurring debt to invest. A better analogy is taking a bank loan to fund a house extension. Building the extension will create value on your house financially, but also socially it will create more space, maybe a home office to allow you to do your job and earn income, maybe a gym so that your family will save on gym memberships and have a much healthier lifestyle. Hard and soft benefits of that investment. the problem we have is that the household debt has skyrocketed under the tories, so when labour go to the bank for the extension loan, the bank see us as a bigger risk (no longer AAA rated) so will charge us more interest, which might mean we never see that financial value in the extension in our lifetime.
We could of course just print money, as a solution to raise capitol to invest, but that isn't consequence free either.
There will be investment under Labour, but it'll be limited because of the absolute car crash of an economy and social system that the tories have created.