Obviously:

The keep-alive method, which shows up on every one of these posts. But as for an actual contact solution, my best advice would be to create a small phosphor bronze stirrup underneath the running boards in the front and back of the loco, and have the bottom of the stirrup gently press against the rail, but that makes it more vulnerable to getting stuck in frogs, joints, and road crossings.

Or you might be able to add a couple of leading and trailing wheels, making a 2-4-2T out of the deal or something?

On an engine as small as this, it's rather difficult to add connections that don't look too obvious.

Is there any space in the cab to allow a bigger flywheel, so that the engine might coast a bit further over the gaps?

more wheels

depends on your prototype location or railroad, but the PRR for example had poling cars which could be attached to your loco for shifting in strange locations. this could be wired up with pickups giving you extra contacts. This PRR 0-4-0 dock shifter gives you an idea of the size. They run on two standard trucks so plenty of wheels. 

longer electrical reach

At one time they made HO scale slider shoe type pickup that could be attached under the front and rear of the engine. I haven't seen these advertised for many years. These sliders or small contact rollers are the common way 3 rail O gauge trains pick up their power....DaveB

@oldstuff: Poling Cars? what was their purpose?

And, while the word came up, What's the purpose of a poling pocket... especially after WWII.  I've never seen their use documented, yet  There They Are!

poling cars?

The poling pockets are shaped to hold the end of a poling pole which can be used to shove cars on adjacent tracks.  Sometimes a car must be poled to clear a switch if the engine can't get by , and sometimes they'd pole a car along an adjacent track to avoid a long run to the switch and back. Poiing died out post WW2 as railroads modernized and loose car count declined ......DaveB

I think poling is now illegal.

It was a very dangerous practice.  You can imagine someone had to hold the pole in place while a locomotiive pushed a poling car into position and the pole had to be tight between the poling car & the freight car being poled.  If the pole broke or came out, it could fly up a injure someone badly.  I'm not sure when it was outlawed, but I think sometime in the late 1950's or early 1960's.

To answer the original post, I think the best way would be to install keep alive in the locomotive.

poling poles

The poling pockets on tenders were used with loose poles. Poling cars had poles permanently attached on pivots at the center point of the car underframe. Marginally less dangerous.

Poling Cars

Very interesting, I've never seen them mentioned before.

Back in the 80's

I was working part time in a freight warehouse.  Somehow a car drifted into a foul point making it impossible for the switch engine to pick it up.  I convinced the engineer we could just pole it back into the clear.  He had no idea what I was talking about.  Using a six foot 4x4 we were able to make this happen.  What a dangerous move on my part.  If he had accelerated a little too fast that 4x4 would have exploded.  We all felt untouchable in our younger life, right?

Docksider Pickup

I have one and unsuccessfully tried additional wipers. The solution was the small decoder with a keep-alive.

Dante

@Dante

Care to give us any details on what decoder and what keep-alive??

Docksider

Brian,

I am away from home so I cannot check the precise model number, but it is a TCS-the smallest they had with an  integral keep-alive. I fit it in the loco cab, vertically.

Dante

Edit: A TCS Kam4 LED. I don't recall why I got the LED version of the Kam4 unless it was the only one available at the time. The Docksider has no lights. 

Docksider Regear

Old Rivarossi CAN run slow!! (Dockside regear)

https://youtu.be/ar6SANQXax