From the Diary of Doctor J. Watson

As we made our way along the tracks, I could make out the outlines of Arthur and Dickie in the darkness.

“I say,” muttered Arthur as we approached. “Funny place to leave a crate.” He pointed to what looked like a wooden packing case sitting close to the rails. It was damaged at one corner as if it had been thrown to the ground. “What d’you suppose it’s doing there?”

I knelt down and examined the box. It was about three feet square with a pair of round holes cut into one side, each about two inches in diameter. There was also a wrought iron hinge on my side, indicating how the thing might be opened. I reached up, intending to lift the lid, but before I could do so, I discerned a faint whirring and clicking noise from within the box. Placing my ear against the rough wood, I listened for a few seconds.

“It’s a fucking bomb – run!” My voice hit a considerably more girlish tone than I’d have hoped, but it did the trick. My companions turned tail and fled to the safety of the trees at the side of the line. I hurried after Mary and crouching down behind a bush, held her close to me in order to assuage any fears she might have at this sudden threat. She in turn slipped her slender fingers into my jacket and gripped my weapon.

I felt the tension rising as we waited for the inevitable explosion, but none came.

After a moment, I stood up and peered at the box from behind the bush. A bright light had flashed on, shining a beam of yellow light through the holes in the side of the crate. The light flickered for ten or twelve seconds then went off.

“Stay put, folks,” I said, “This might be some sort of smuggler’s trickery.”

We watched for a while, but the box only emitted a further series of clicking sounds followed by occasional flashes of light.

Mary touched my arm. “D’you think this is the same light we saw from the platform?”

I nodded. “Perhaps.”

Dickie came out from behind a tree. “Actually it looks a bit like one of those steam-operated Brighty-Lighty contraptions.”

I must have looked a bit blank for he continued, “They use them in the theatre for special effects. Look here…” He advanced towards the box and pulled up the lid. “There – see?” He reached inside and fiddled with a couple of knobs. “Looks like it’s been damaged. The lens has broken.”

We gathered around and sure enough the inside of the crate was filled with a small mechanical engine and a copper water-flask from which occasional bursts of vapour erupted.

“What does it do, exactly? I said.

“It’s a sort of lantern show,” said Arthur, doing a little dance. “Projects pictures or coloured lights against a white screen to enhance the performance of the artistes. Dickie and I used one at Blackpool last year.” He turned to Mary. “I look quite fetching against a pink background, you know.”

Mary giggled, but I was puzzled. “That wouldn’t work here – there’s no screen.”

Mary tugged my sleeve. “Perhaps the station itself is the screen?”

“You mean…the image is projected onto the windows of the station to give the effect of a train passing through?”

“Yes,” she said. “After all, we didn’t actually see the train, did we? Only a lot of lights and noise.”

I shook my head. “That’s a nice theory darling, but I’m afraid it’s bollocks. As you say, we did hear the noise of the locomotive, but what about the rattling of the windows and the vibration in the floor? How d’you explain that, eh? You can’t do all that with a mere lantern show.”

She pulled a face. “I’m just trying to be helpful.”

I began to wish Holmes was with us – he at least would have several theories, no doubt including the actual solution to the mystery. “I think we’d better take this back to the station.”

We spent the next few minutes manhandling the crate back up the line and onto the platform. As we clambered up, the waiting room door opened and the young man looked out.

“Thank Christ you’re back. It’s the stationmaster – I think he’d dead!”