"Ekiben" Rail Station Box Lunch
This is sushi rice topped with Hokkaido's specialty seafoods: sliced raw salmon, boiled crab legs and "ikura" salmon roe, with a side of pickled aubergine/eggplant and wrapped seaweed with a little shredded scrambled egg. The cost is a little on the higher end of the "ekiben" spectrum, due to the use of fanciful fishes. These sorts of ingredients, however though special to Hokkaido (and probably relatively cheaper) is also widely available elsewhere in Japan, so I think there is a somewhat lessened effect of eating a "uniquely local specialty". But still it's quite tasty!
Generally, it is available for purchase only in this area, primarily at Kushiro Station.
Manufactured by local company KK Senshokan which was founded in the year 1953.

Leaving Gojikkoku station, Hokkaido
Along the Sekihoku line, Hokkaido