For decades the traffic on the MOB had been handled by electric railcars available in four-, six- and eight-axle designs. In 1983, four modern locomotives, type GDe4/4 6001-6004, were added and they are most frequently seen heading up the Panoramic Express. Apart from the through trains between Montreux and Zweisimmen and between Montreux and Lenk, there is hourly local service serving Montreux-Les Avants, Gstaad-Zweisimmen and Zweisimmen-Lenk.
The MOB is run with 900 V direct current and has very steep gradients of up to 7,3 %. It begins in Montreux near the SBB station and the rack and pinion railway to Rochers de Naye, winding its way up through the vineyards above Lake Geneva via Chamby as far as Les Avants. After passing through the crown tunnel under the Col de Jaman it reaches the Saane Valley. In Montbovon there is a connection to the GFM network. Following the Saane upstream, it leaves the French-speaking Canton of Vaud near Rougemont and enters the German-speaking Canton of Bern. Beyond Gstaad it begins the climb to the head of Saanenmöser Pass, the highest point on the line. On the other side it descends into the Simmen Valley to Zweisimmen, where there is a connection to the standard-gauge line of the BLS group to Spiez. For the MOB, Zweisimmen is the terminus station; the branch line to Lenk continues in the opposite direction. Because of its poor state of repair, this line stood on the brink of closure in 1975. However, it was fully modernized in 1977-1979, received new tracks and overhead lines and since then is included in the regular operating schedule of the MOB. This entire line opens up a region of awe-inspiring scenic beauty and unending variety; a most unforgettable experience is, of course, the trip in the air-conditioned dome cars of the Panoramic Express, which plys the route twice a day and is not subject to change.