Cover with 'Moravian Mission, Bluefields, Nic' return address at lower left franked with 1904 15c deep blue 'Momotombo' TRAIN issue with 'B Dpto Zelaya' overprint in black (SG B5) tied by oval BLUEFIELDS cancel with good strike of straight line 'OUT SIDE MAIL' alongside. Addressed to USA with arrival marks on reverse. The 15c is scarce on cover.