Kaor fellow travelers!
I wanted to see if I’m ruling this right: per the RAW, the Travelling Pool consists of Successes n Momentum, right?
Even if these Successes do not beat the Difficulty, right? IE, the Difficulty is 4, but only 3 Successes were generated - are these added to the TP (even though the Difficulty wasn’t beat)?
Thanks
I would say no and rule it as such, but–just as a warning–I may be wrong. If so I hope more knowledgeable heads will set the record straight.
If the test Difficulty Number was not met in Successes, then the test failed, and no points would be added to the Travel Pool–regardless of how many were generated.
A point is added to the Travel Pool by:
1.) successfully meeting the Difficulty Number–1 point, or
2.) contributing any additional successes, now Momentum, to the Pool
In the example, Jane won the test. The terrain was “Rocky terrain, swamps, and wastelands,” or its equivalent, which was D1 test requiring a single success. She must have rolled a combination of three success. One was automatically added to the Travel Pool as a point for successfully meeting the D1 test requirement. The remaining two successes generated two momentum. One she voluntarily contributed to the Travel Pool (smart girl); and one she pocketed for herself (smarter girl).
If, however, she had been traveling through the same terrain (D1) AND there was a severe storm (+D2) AND she was on foot (+D1)–not so smart girls, it would have been a D4 test rather than a D1 test. Her three successes would have resulted in test failure. She would have made no progress, NO point would have been added to the Travel Pool, and no extra successes translated to Momentum.
After a failed test, NO points (regardless of the number of successes rolled) are added to the Travel Pool, i.e. the test failed and, therefore, it was NOT successful and generated nothing. This is very much in keeping with a normal Attribute test: if a character fails, regardless of the number of successes rolled, no beyond-the-target-number, extra success-generated Momentum is available to be spent or added to their Momentum Pool–the test failed, was not successful and, therefore, generated nothing to contribute in terms of potential Momentum.
BUT…as always…your John Carter of Mars game may vary 
Cheers
Thanks for your enlightening answer! With the «permissive successes» ruling, the travel pool was enormous, even when traversing the most perilous terrain!