I actually went to an old school hobby store and they had a box of partially used miscellaneous decal sheet sets, and I came across Microscale #91138 (4" and 6" stripes). While these are not bright yellow, I think they will serve the purpose.
www.microscale.com
As a bonus, they also had a set of generic CN steam loco (1931-1960) decals so I can finally decorate an old Mehano Pacific 4-6-2 I inherited from my dad almost 30 years ago.
www.microscale.com
Going direct to Microscale incurs shipping and handling fees, minimum order size, exchange rate and possibly duties/brokerage fees. So I kinda lucked out finding these two sets kicking around in a box that looked like they've been there since the 70's.