Venunder, on 01 August 2012 - 11:00 PM, said:
That is the Grey Battery box cover? So Lego have corrected this by including a red cover for the battery box. :)

lightningtiger, on 01 August 2012 - 11:12 PM, said:
Ah, if you read - it's a sticker....a plain red sticker.
Neat idea 'JopieK', who knows when I get to build mine I might do the same perhaps ?

I think what Venunder means is there is a red battery box cover in the 3677 set. The problem is it's designed for the 6xAAA battery box, not the rechargeable battery box, so if you want to use the rechargeable battery box a solution such as stickers must be found.
Another solution is to dismantle your rechargeable battery and fit it inside the red cover. I'm pretty sure this was reported possible somewhere on Train Tech in the past.