Calgary - A blinking light on the dispatcher's board in the Palliser Square central dispatch office was the first indication that something was amiss above the Spiral Tunnels at about 21:00 hours, Wednesday, 6 Sep 1978. The light warned of a break in the electronic slide fence on Cathedral Mountain, above Partridge siding at mileage 128 on the Laggan subdivision, west of Calgary.

The cause of the break couldn't be determined, but dispatcher K.W. Enzie knew that "extra 8827 west" was passing through the area. Normal procedure called for telephone contact to be made with the operator at Field, B.C., and for that operator to advise the train crew of the situation by radio.

Dispatcher Enzie immediately phoned Maureen Smythe, the Field operator. Conductor Bob Roberts didn't receive her radio call, however, probably because of poor atmospheric conditions. "Extra 8827 west", a 30 car train consisting mainly of empty cars, slammed unexpectedly to a stop, sending the conductor and tail-end brakeman Dan Nadasdi sprawling.

Following the impact Conductor Roberts attempted to contact the head-end by radio. He got no reply.

Up at the head-end, engineman Bob Palser and Brian Materi, head-end brakeman, scrambled out of the cab of the lead unit. They both heard the heavy rumbling sound of a slide in progress. Following a quick inspection they saw that both diesel units were buried window-deep in silt and rock. More loose rock continued to cascade down the mountain, water was rushing through the debris, and pieces of ice were visible.

The two men left the slide scene and made their way to Field. Brakeman Materi was able to flag down a car on the Trans-Canada highway and Engineman Palser walked down the slope to Cathedral where he boarded a caboose-hop stopped in the siding and rode back to Field to report in.

Back at the tail-end Conductor Roberts and Brakeman Nadasdi began to walk to the head-end to check for the rest of the train crew. On the way they encountered an extra gang staying in boarding cars on a back track in Yoho Yard.

Realizing a slide was in progress Conductor Roberts advised Brakeman Nadasdi to suggest that the extra gang take shelter in the mouth of the Spiral Tunnel.

At the head-end of the train conductor Roberts learned by radio from Wes Cudney, yardmaster at Field, that the headend crew was safe and clear of the slide. Following that message he returned to the tunnel.

The roar of rocks plummeting down the dark and rain enshrouded mountain continued until midnight.

When Mike Stroick, superintendent for the Calgary Division, was informed of the situation at Cathedral Mountain he immediately issued orders that no one was to venture into the slide path until it was established it was safe to do so.

After an examination of the area by Mr. Stroick and other divisional officers it was determined entry into the area was safe. The all clear order was issued at about 02:30, Thursday.

Mr. Stroick, Louis Visocchi, roadmaster from Banff, and Bernie Zinger, surfacing gang foremen, walked up to the Spiral Tunnel to deliver the all clear to the personnel within.

Track clearing work commenced at sunrise Thursday.